Method and apparatus for transmitting downlink control information in wireless communication system

ABSTRACT

A method and apparatus for monitoring downlink control information (DCI) in a wireless communication system, especially in a new radio access technology (NR) is provided. A user equipment (UE) monitors first DCI having a first size in a UE specific search space (USS). The first size is determined based on an active bandwidth part (BWP). The UE further monitors second DCI having a second size in a common search space (CSS). The second size is determined based on a default BWP.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/303,970, filed on Nov. 21, 2018, which is National Stage applicationunder 35 U.S.C. § 371 of International Application No.PCT/KR2018/010640, filed on Sep. 11, 2018, which claims the benefit ofKorean Application No. 10-2018-0108419, filed on Sep. 11, 2018, U.S.Provisional Application No. 62/630,236, filed on Feb. 13, 2018, U.S.Provisional Application No. 62/593,991, filed on Dec. 3, 2017, U.S.Provisional Application No. 62/587,521, filed on Nov. 17, 2017, U.S.Provisional Application No. 62/558,862, filed on Sep. 15, 2017, and U.S.Provisional Application No. 62/557,124, filed on Sep. 11, 2017. Thedisclosures of the prior applications are incorporated by reference intheir entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to wireless communications, and moreparticularly, to a method and apparatus for designing/transmittingdownlink control information (DCI) and/or determining a transport blocksize (TBS) in a new radio access technology (NR) system.

Related Art

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

Work has started in international telecommunication union (ITU) and 3GPPto develop requirements and specifications for new radio (NR) systems.3GPP has to identify and develop the technology components needed forsuccessfully standardizing the new RAT timely satisfying both the urgentmarket needs, and the more long-term requirements set forth by the ITUradio communication sector (ITU-R) international mobiletelecommunications (IMT)-2020 process. Further, the NR should be able touse any spectrum band ranging at least up to 100 GHz that may be madeavailable for wireless communications even in a more distant future.

The NR targets a single technical framework addressing all usagescenarios, requirements and deployment scenarios including enhancedmobile broadband (eMBB), massive machine-type-communications (mMTC),ultra-reliable and low latency communications (URLLC), etc. The NR shallbe inherently forward compatible.

There are various downlink control information (DCI) formats used in LTEin a control channel. The DCI format is a predefined format in which theDCI is packed/formed and transmitted in the control channel. The DCIformats tell a user equipment (UE) how to transmit/receive its data on adata channel. So, based on the DCI format transmitted in the controlchannel, a UE can transmit/receive data. The DCI format gives the UE,details such as number of resource blocks, resource allocation type,modulation scheme, transport block, redundancy version, coding rate etc.

NR may also use DCI formats. But, enhancements for DCI formats should berequired to reflect the features of NR.

SUMMARY OF THE INVENTION

The present invention discusses DCI design aspects and TBS determinationrelated to NR.

In an aspect, a method for monitoring downlink control information (DCI)by a user equipment (UE) in a wireless communication system is provided.The method includes monitoring first DCI having a first size in a UEspecific search space (USS), wherein the first size is determined basedon an active bandwidth part (BWP), and monitoring second DCI having asecond size in a common search space (CSS), wherein the second size isdetermined based on a default BWP.

In another aspect, a user equipment (UE) in a wireless communicationsystem is provided. The UE includes a memory, a transceiver, and aprocessor, operably coupled to the memory and the transceiver, thatcontrols the transceiver to monitor first downlink control information(DCI) having a first size in a UE specific search space (USS), whereinthe first size is determined based on an active bandwidth part (BWP),and controls the transceiver to monitor second DCI having a second sizein a common search space (CSS), wherein the second size is determinedbased on a default BWP.

In another aspect, a method for transmitting downlink controlinformation (DCI) by a base station (BS) in a wireless communicationsystem is provided. The method includes transmitting first DCI having afirst size in a UE specific search space (USS), wherein the first sizeis determined based on an active bandwidth part (BWP), and transmittingsecond DCI having a second size in a common search space (CSS), whereinthe second size is determined based on a default BWP.

DCI can be designed efficiently for NR. Furthermore, TBS can bedetermined efficiently for NR.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a wireless communication system to whichtechnical features of the present invention can be applied.

FIG. 2 shows another example of a wireless communication system to whichtechnical features of the present invention can be applied.

FIG. 3 shows an example of a frame structure to which technical featuresof the present invention can be applied.

FIG. 4 shows another example of a frame structure to which technicalfeatures of the present invention can be applied.

FIG. 5 shows an example of a resource grid to which technical featuresof the present invention can be applied.

FIG. 6 shows an example of a synchronization channel to which technicalfeatures of the present invention can be applied.

FIG. 7 shows an example of a frequency allocation scheme to whichtechnical features of the present invention can be applied.

FIG. 8 shows an example of multiple BWPs to which technical features ofthe present invention can be applied.

FIG. 9 shows an example of relationship between various features, DL DCIformats, UL DCI formats, size of DCI formats and CORESET according to anembodiment of the present invention.

FIG. 10 shows an example of frequency resource region to allow sharingof CSS among different BWPs according to an embodiment of the presentinvention.

FIG. 11 shows an example for frequency-domain resource allocation for agiven BWP according to an embodiment of the present invention.

FIG. 12 shows an example of indicating PRB offset between subcarrier 0and SS block in terms of number of RBs based on the numerology used forPBCH according to an embodiment of the present invention.

FIG. 13 shows a method for monitoring DCI by a UE according to anembodiment of the present invention.

FIG. 14 shows a UE to implement an embodiment of the present invention.

FIG. 15 shows a method for transmitting DCI by a BS according to anembodiment of the present invention.

FIG. 16 shows a BS to implement an embodiment of the present invention.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The technical features described below may be used by a communicationstandard by the 3rd generation partnership project (3GPP)standardization organization, a communication standard by the instituteof electrical and electronics engineers (IEEE), etc. For example, thecommunication standards by the 3GPP standardization organization includelong-term evolution (LTE) and/or evolution of LTE systems. The evolutionof LTE systems includes LTE-advanced (LTE-A), LTE-A Pro, and/or 5G newradio (NR). The communication standard by the IEEE standardizationorganization includes a wireless local area network (WLAN) system suchas IEEE 802.11a/b/g/n/ac/ax. The above system uses various multipleaccess technologies such as orthogonal frequency division multipleaccess (OFDMA) and/or single carrier frequency division multiple access(SC-FDMA) for downlink (DL) and/or uplink (DL). For example, only OFDMAmay be used for DL and only SC-FDMA may be used for UL. Alternatively,OFDMA and SC-FDMA may be used for DL and/or UL.

FIG. 1 shows an example of a wireless communication system to whichtechnical features of the present invention can be applied.Specifically, FIG. 1 shows a system architecture based on anevolved-UMTS terrestrial radio access network (E-UTRAN). Theaforementioned LTE is a part of an evolved-UTMS (e-UMTS) using theE-UTRAN.

Referring to FIG. 1, the wireless communication system includes one ormore user equipment (UE; 10), an E-UTRAN and an evolved packet core(EPC). The UE 10 refers to a communication equipment carried by a user.The UE 10 may be fixed or mobile. The UE 10 may be referred to asanother terminology, such as a mobile station (MS), a user terminal(UT), a subscriber station (SS), a wireless device, etc.

The E-UTRAN consists of one or more base station (BS) 20. The BS 20provides the E-UTRA user plane and control plane protocol terminationstowards the UE 10. The BS 20 is generally a fixed station thatcommunicates with the UE 10. The BS 20 hosts the functions, such asinter-cell radio resource management (MME), radio bearer (RB) control,connection mobility control, radio admission control, measurementconfiguration/provision, dynamic resource allocation (scheduler), etc.The BS may be referred to as another terminology, such as an evolvedNodeB (eNB), a base transceiver system (BTS), an access point (AP), etc.

A downlink (DL) denotes communication from the BS 20 to the UE 10. Anuplink (UL) denotes communication from the UE 10 to the BS 20. Asidelink (SL) denotes communication between the UEs 10. In the DL, atransmitter may be a part of the BS 20, and a receiver may be a part ofthe UE 10. In the UL, the transmitter may be a part of the UE 10, andthe receiver may be a part of the BS 20. In the SL, the transmitter andreceiver may be a part of the UE 10.

The EPC includes a mobility management entity (MME), a serving gateway(S-GW) and a packet data network (PDN) gateway (P-GW). The MME hosts thefunctions, such as non-access stratum (NAS) security, idle statemobility handling, evolved packet system (EPS) bearer control, etc. TheS-GW hosts the functions, such as mobility anchoring, etc. The S-GW is agateway having an E-UTRAN as an endpoint. For convenience, MME/S-GW 30will be referred to herein simply as a “gateway,” but it is understoodthat this entity includes both the MME and S-GW. The P-GW hosts thefunctions, such as UE Internet protocol (IP) address allocation, packetfiltering, etc. The P-GW is a gateway having a PDN as an endpoint. TheP-GW is connected to an external network.

The UE 10 is connected to the BS 20 by means of the Uu interface. TheUEs 10 are interconnected with each other by means of the PC5 interface.The BSs 20 are interconnected with each other by means of the X2interface. The BSs 20 are also connected by means of the S1 interface tothe EPC, more specifically to the MME by means of the S1-MME interfaceand to the S-GW by means of the S1-U interface. The S1 interfacesupports a many-to-many relation between MMES/S-GWs and BSs.

FIG. 2 shows another example of a wireless communication system to whichtechnical features of the present invention can be applied.Specifically, FIG. 2 shows a system architecture based on a 5G new radioaccess technology (NR) system. The entity used in the 5G NR system(hereinafter, simply referred to as “NR”) may absorb some or all of thefunctions of the entities introduced in FIG. 1 (e.g. eNB, MME, S-GW).The entity used in the NR system may be identified by the name “NG” fordistinction from the LTE.

Referring to FIG. 2, the wireless communication system includes one ormore UE 11, a next-generation RAN (NG-RAN) and a 5th generation corenetwork (5GC). The NG-RAN consists of at least one NG-RAN node. TheNG-RAN node is an entity corresponding to the BS 10 shown in FIG. 1. TheNG-RAN node consists of at least one gNB 21 and/or at least one ng-eNB22. The gNB 21 provides NR user plane and control plane protocolterminations towards the UE 11. The ng-eNB 22 provides E-UTRA user planeand control plane protocol terminations towards the UE 11.

The 5GC includes an access and mobility management function (AMF), auser plane function (UPF) and a session management function (SMF). TheAMF hosts the functions, such as NAS security, idle state mobilityhandling, etc. The AMF is an entity including the functions of theconventional MME. The UPF hosts the functions, such as mobilityanchoring, protocol data unit (PDU) handling. The UPF an entityincluding the functions of the conventional S-GW. The SMF hosts thefunctions, such as UE IP address allocation, PDU session control.

The gNBs and ng-eNBs are interconnected with each other by means of theXn interface. The gNBs and ng-eNBs are also connected by means of the NGinterfaces to the 5GC, more specifically to the AMF by means of the NG-Cinterface and to the UPF by means of the NG-U interface.

A structure of a radio frame in NR is described. In LTE/LTE-A, one radioframe consists of 10 subframes, and one subframe consists of 2 slots. Alength of one subframe may be 1 ms, and a length of one slot may be 0.5ms. Time for transmitting one transport block by higher layer tophysical layer (generally over one subframe) is defined as atransmission time interval (TTI). A TTI may be the minimum unit ofscheduling.

Unlike LTE/LTE-A, NR supports various numerologies, and accordingly, thestructure of the radio frame may be varied. NR supports multiplesubcarrier spacings in frequency domain. Table 1 shows multiplenumerologies supported in NR. Each numerology may be identified by indexμ.

TABLE 1 Subcarrier Supported for Supported for μ spacing (kHz) Cyclicprefix data synchronization 0 15 Normal Yes Yes 1 30 Normal Yes Yes 2 60Normal, Yes No Extended 3 120 Normal Yes Yes 4 240 Normal No Yes

Referring to Table 1, a subcarrier spacing may be set to any one of 15,30, 60, 120, and 240 kHz, which is identified by index μ. However,subcarrier spacings shown in Table 1 are merely exemplary, and specificsubcarrier spacings may be changed. Therefore, each subcarrier spacing(e.g. μ=0,1 . . . 4) may be represented as a first subcarrier spacing, asecond subcarrier spacing . . . Nth subcarrier spacing.

Referring to Table 1, transmission of user data (e.g. physical uplinkshared channel (PUSCH), physical downlink shared channel (PDSCH)) maynot be supported depending on the subcarrier spacing. That is,transmission of user data may not be supported only in at least onespecific subcarrier spacing (e.g. 240 kHz).

In addition, referring to Table 1, a synchronization channel (e.g. aprimary synchronization signal (PSS), a secondary synchronization signal(SSS), a physical broadcast channel (PBCH)) may not be supporteddepending on the subcarrier spacing. That is, the synchronizationchannel may not be supported only in at least one specific subcarrierspacing (e.g. 60 kHz).

In NR, a number of slots and a number of symbols included in one radioframe/subframe may be different according to various numerologies, i.e.various subcarrier spacings. Table 2 shows an example of a number ofOFDM symbols per slot, slots per radio frame, and slots per subframe fornormal cyclic prefix (CP).

TABLE 2 Number of symbols Number of slots per Number of slots per μ perslot radio frame subframe 0 14 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14160 16

Referring to Table 2, when a first numerology corresponding to μ=0 isapplied, one radio frame includes 10 subframes, one subframe correspondsto one slot, and one slot consists of 14 symbols. In the presentspecification, a symbol refers to a signal transmitted during a specifictime interval. For example, a symbol may refer to a signal generated byOFDM processing. That is, a symbols in the present specification mayrefer to an OFDM/OFDMA symbol, or SC-FDMA symbol, etc. A CP may belocated between each symbol.

FIG. 3 shows an example of a frame structure to which technical featuresof the present invention can be applied. In FIG. 3, a subcarrier spacingis 15 kHz, which corresponds to μ=0.

FIG. 4 shows another example of a frame structure to which technicalfeatures of the present invention can be applied. In FIG. 4, asubcarrier spacing is 30 kHz, which corresponds to μ=1.

Table 3 shows an example of a number of OFDM symbols per slot, slots perradio frame, and slots per subframe for extended CP.

TABLE 3 Number of symbols Number of slots per Number of slots per μ perslot radio frame subframe 2 12 40 4

Meanwhile, a frequency division duplex (FDD) and/or a time divisionduplex (TDD) may be applied to a wireless system to which an embodimentof the present invention is applied. When TDD is applied, in LTE/LTE-A,UL subframes and DL subframes are allocated in units of subframes.

In NR, symbols in a slot may be classified as a DL symbol (denoted byD), a flexible symbol (denoted by X), and a UL symbol (denoted by U). Ina slot in a DL frame, the UE shall assume that DL transmissions onlyoccur in DL symbols or flexible symbols. In a slot in an UL frame, theUE shall only transmit in UL symbols or flexible symbols.

Table 4 shows an example of a slot format which is identified by acorresponding format index. The contents of the Table 4 may be commonlyapplied to a specific cell, or may be commonly applied to adjacentcells, or may be applied individually or differently to each UE.

TABLE 4 For- Symbol number in a slot mat 0 1 2 3 4 5 6 7 8 9 10 11 12 130 D D D D D D D D D D D D D D 1 U U U U U U U U U U U U U U 2 X X X X XX X X X X X X X X 3 D D D D D D D D D D D D D X 4 D D D D D D D D D D DD X X 5 D D D D D D D D D D D X X X 6 D D D D D D D D D D X X X X 7 D DD D D D D D D X X X X X 8 X X X X X X X X X X X X X U 9 X X X X X X X XX X X X U U 10 X U U U U U U U U U U U U U 11 X X U U U U U U U U U U UU 12 X X X U U U U U U U U U U U 13 X X X X U U U U U U U U U U 14 X X XX X U U U U U U U U U 15 X X X X X X U U U U U U U U 16 D X X X X X X XX X X X X X 17 D D X X X X X X X X X X X X 18 D D D X X X X X X X X X XX 19 D X X X X X X X X X X X X U 20 D D X X X X X X X X X X X U 21 D D DX X X X X X X X X X U 22 D X X X X X X X X X X X U U 23 D D X X X X X XX X X X U U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .

For convenience of explanation, Table 4 shows only a part of the slotformat actually defined in NR. The specific allocation scheme may bechanged or added.

The UE may receive a slot format configuration via a higher layersignaling (i.e. radio resource control (RRC) signaling). Or, the UE mayreceive a slot format configuration via downlink control information(DCI) which is received on PDCCH. Or, the UE may receive a slot formatconfiguration via combination of higher layer signaling and DCI.

FIG. 5 shows an example of a resource grid to which technical featuresof the present invention can be applied. An example shown in FIG. 5 is atime-frequency resource grid used in NR. An example shown in FIG. 5 maybe applied to UL and/or DL. Referring to FIG. 5, multiple slots areincluded within one subframe on the time domain. Specifically, whenexpressed according to the value of “μ”, “14.2μ” symbols may beexpressed in the resource grid. Also, one resource block (RB) may occupy12 consecutive subcarriers. One RB may be referred to as a physicalresource block (PRB), and 12 resource elements (REs) may be included ineach PRB. The number of allocatable RBs may be determined based on aminimum value and a maximum value. The number of allocatable RBs may beconfigured individually according to the numerology (“μ”). The number ofallocatable RBs may be configured to the same value for UL and DL, ormay be configured to different values for UL and DL.

A cell search scheme in NR is described. The UE may perform cell searchin order to acquire time and/or frequency synchronization with a celland to acquire a cell identifier (ID). Synchronization channels such asPSS, SSS, and PBCH may be used for cell search.

FIG. 6 shows an example of a synchronization channel to which technicalfeatures of the present invention can be applied. Referring to FIG. 6,the PSS and SSS may include one symbol and 127 subcarriers. The PBCH mayinclude 3 symbols and 240 subcarriers.

The PSS is used for synchronization signal/PBCH block (SSB) symboltiming acquisition. The PSS indicates 3 hypotheses for cell IDidentification. The SSS is used for cell ID identification. The SSSindicates 336 hypotheses. Consequently, 1008 physical layer cell IDs maybe configured by the PSS and the SSS.

The SSB block may be repeatedly transmitted according to a predeterminedpattern within the 5 ms window. For example, when L SSB blocks aretransmitted, all of SSB #1 through SSB #L may contain the sameinformation, but may be transmitted through beams in differentdirections. That is, quasi co-located (QCL) relationship may not beapplied to the SSB blocks within the 5 ms window. The beams used toreceive the SSB block may be used in subsequent operations between theUE and the network (e.g. random access operations). The SSB block may berepeated by a specific period. The repetition period may be configuredindividually according to the numerology.

Referring to FIG. 6, the PBCH has a bandwidth of 20 RBs for the 2nd/4thsymbols and 8 RBs for the 3rd symbol. The PBCH includes a demodulationreference signal (DM-RS) for decoding the PBCH. The frequency domain forthe DM-RS is determined according to the cell ID. Unlike LTE/LTE-A,since a cell-specific reference signal (CRS) is not defined in NR, aspecial DM-RS is defined for decoding the PBCH (i.e. PBCH-DMRS). ThePBCH-DMRS may contain information indicating an SSB index.

The PBCH performs various functions. For example, the PBCH may perform afunction of broadcasting a master information block (MIB). Systeminformation (SI) is divided into a minimum SI and other SI. The minimumSI may be divided into MIB and system information block type-1 (SIB1).The minimum SI excluding the MIB may be referred to as a remainingminimum SI (RMSI). That is, the RMSI may refer to the SIB1.

The MIB includes information necessary for decoding SIB1. For example,the MIB may include information on a subcarrier spacing applied to SIB1(and MSG 2/4 used in the random access procedure, other SI), informationon a frequency offset between the SSB block and the subsequentlytransmitted RB, information on a bandwidth of the PDCCH/SIB, andinformation for decoding the PDCCH (e.g. information onsearch-space/control resource set (CORESET)/DM-RS, etc., which will bedescribed later). The MIB may be periodically transmitted, and the sameinformation may be repeatedly transmitted during 80 ms time interval.The SIB1 may be repeatedly transmitted through the PDSCH. The SIB1includes control information for initial access of the UE andinformation for decoding another SIB.

PDCCH decoding in NR is described. The search space for the PDCCHcorresponds to an area in which the UE performs blind decoding on thePDCCH. In LTE/LTE-A, the search space for the PDCCH is divided into acommon search space (CSS) and a UE-specific search space (USS). The sizeof each search space and/or the size of a control channel element (CCE)included in the PDCCH are determined according to the PDCCH format.

In NR, a resource-element group (REG) and a CCE for the PDCCH aredefined. In NR, the concept of CORESET is defined. Specifically, one REGcorresponds to 12 REs, i.e. one RB transmitted through one OFDM symbol.Each REG includes a DM-RS. One CCE includes a plurality of REGs (e.g. 6REGs). The PDCCH may be transmitted through a resource consisting of 1,2, 4, 8, or 16 CCEs. The number of CCEs may be determined according tothe aggregation level. That is, one CCE when the aggregation level is 1,2 CCEs when the aggregation level is 2, 4 CCEs when the aggregationlevel is 4, 8 CCEs when the aggregation level is 8, 16 CCEs when theaggregation level is 16, may be included in the PDCCH for a specific UE.

The CORESET may be defined on 1/2/3 OFDM symbols and multiple RBs. InLTE/LTE-A, the number of symbols used for the PDCCH is defined by aphysical control format indicator channel (PCFICH). However, the PCFICHis not used in NR. Instead, the number of symbols used for the CORESTmay be defined by the RRC message (and/or PBCH/SIB1). Also, inLTE/LTE-A, since the frequency bandwidth of the PDCCH is the same as theentire system bandwidth, so there is no signaling regarding thefrequency bandwidth of the PDCCH. In NR, the frequency domain of theCORESET may be defined by the RRC message (and/or PBCH/SIB1) in a unitof RB.

In NR, the search space for the PDCCH is divided into CSS and USS. Sincethe USS may be indicated by the RRC message, an RRC connection may berequired for the UE to decode the USS. The USS may include controlinformation for PDSCH decoding assigned to the UE.

Since the PDCCH needs to be decoded even when the RRC configuration isnot completed, CSS should also be defined. For example, CSS may bedefined when a PDCCH for decoding a PDSCH that conveys SIB1 isconfigured or when a PDCCH for receiving MSG 2/4 is configured in arandom access procedure. Like LTE/LTE-A, in NR, the PDCCH may bescrambled by a radio network temporary identifier (RNTI) for a specificpurpose.

A resource allocation scheme in NR is described. In NR, a specificnumber (e.g. up to 4) of bandwidth parts (BPWs) may be defined. A BWP(or carrier BWP) is a set of consecutive PRBs, and may be represented bya consecutive subsets of common RBs (CRBs). Each RB in the CRB may berepresented by CRB1, CRB2, etc., beginning with CRB0.

FIG. 7 shows an example of a frequency allocation scheme to whichtechnical features of the present invention can be applied. Referring toFIG. 7, multiple BWPs may be defined in the CRB grid. A reference pointof the CRB grid (which may be referred to as a common reference point, astarting point, etc.) is referred to as so-called “point A” in NR. Thepoint A is indicated by the RMSI (i.e. SIB1). Specifically, thefrequency offset between the frequency band in which the SSB block istransmitted and the point A may be indicated through the RMSI. The pointA corresponds to the center frequency of the CRB0. Further, the point Amay be a point at which the variable “k” indicating the frequency bandof the RE is set to zero in NR. The multiple BWPs shown in FIG. 7 isconfigured to one cell (e.g. primary cell (PCell)). A plurality of BWPsmay be configured for each cell individually or commonly.

Referring to FIG. 7, each BWP may be defined by a size and startingpoint from CRB0. For example, the first BWP, i.e. BWP #0, may be definedby a starting point through an offset from CRB0, and a size of the BWP#0 may be determined through the size for BWP #0.

A specific number (e.g., up to four) of BWPs may be configured for theUE. At a specific time point, only a specific number (e.g. one) of BWPsmay be active per cell. The number of configurable BWPs or the number ofactivated BWPs may be configured commonly or individually for UL and DL.The UE can receive PDSCH, PDCCH and/or channel state information (CSI)RS only on the active DL BWP. Also, the UE can transmit PUSCH and/orphysical uplink control channel (PUCCH) only on the active UL BWP.

FIG. 8 shows an example of multiple BWPs to which technical features ofthe present invention can be applied. Referring to FIG. 8, 3 BWPs may beconfigured. The first BWP may span 40 MHz band, and a subcarrier spacingof 15 kHz may be applied. The second BWP may span 10 MHz band, and asubcarrier spacing of 15 kHz may be applied. The third BWP may span 20MHz band and a subcarrier spacing of 60 kHz may be applied. The UE mayconfigure at least one BWP among the 3 BWPs as an active BWP, and mayperform UL and/or DL data communication via the active BWP.

A time resource may be indicated in a manner that indicates a timedifference/offset based on a transmission time point of a PDCCHallocating DL or UL resources. For example, the start point of thePDSCH/PUSCH corresponding to the PDCCH and the number of symbolsoccupied by the PDSCH/PUSCH may be indicated.

Carrier aggregation (CA) is described. Like LTE/LTE-A, CA can besupported in NR. That is, it is possible to aggregate continuous ordiscontinuous component carriers (CCs) to increase the bandwidth andconsequently increase the bit rate. Each CC may correspond to a(serving) cell, and each CC/cell may be divided into a primary servingcell (PSC)/primary CC (PCC) or a secondary serving cell (SSC)/secondaryCC (SCC).

Hereinafter, various aspects of the present invention is describedaccording to embodiments of the present invention.

1. Differentiation Between Mini-Slot and Slot

As mentioned above, a slot is a basic unit for scheduling in NR.Furthermore, a mini-slot may be defined. The mini-slot may be asupplemental unit for scheduling. A length of the mini-slot is shorterthan a length of the slot. The slot may include multiple mini-slots.

Properties of the slot based scheduling and the mini-slot basedscheduling may be different. Firstly, the duration of mini-slot basedscheduling may not exceed the duration of slot, unless mini-slotaggregation is also supported. To support longer duration than the slot,multi-slot with variable start and end positions in each slot may beutilized, instead of mini-slot aggregation. Furthermore, the schedulingDCI may be present at any time during the slot. In other words,scheduling DCI may be transmitted from a CORESET placed in the firstOFDM symbols of the slot, or scheduling DCI may be transmitted from aCORESET placed in the middle or last part of the slot. Furthermore, thelocation of demodulation reference signal (DM-RS) and its selectablepatterns may also be different between mini-slot based scheduling andslot based scheduling. Also, resource allocation in multi-mini-slotbased scheduling may be contiguous, whereas resource allocation inmulti-slot based scheduling may be discontinuous due to gap or ULresources between slots. As at least time-domain resources or resourceallocation may be different between mini-slot based scheduling andslot-based scheduling, a UE may need to differentiate mini-slot basedscheduling and slot based scheduling.

The followings are approaches to differentiate mini-slot basedscheduling and slot based scheduling and interpret the associatedresource allocation fields.

(1) Implicit differentiation: Only slot based scheduling may bescheduled in a CORESET. A monitoring periodicity of the CORESET/searchspace set may be multiple of slots. Or, location of the CORESET/searchspace set may be in the first few OFDM symbols. Or, the end OFDM symbolof the CORESET may be before the first OFDM symbol of indicated DM-RSposition for data transmission. Alternatively, CORESET/search space setmay schedule only slot based scheduling, unless indicated otherwise. Inother words, default behaviour of a CORESET/search space set may be toschedule a slot based scheduling. The slot based scheduling may alsoinclude multi-slot based scheduling. The slot based scheduling may beoverwritten by explicit configuration. When slot based scheduling issupported, the multi-slot based scheduling may be supported withsemi-statically fixed value and dynamically indicated number of slots.

(2) Explicit configuration per each CORESET or per each search space setor per each DCI format or per each DCI size in a CORESET: A set of startand end positions of PDSCH and PUSCH, respectively, may be explicitlyconfigured. The set of start and end positions of PDSCH and PUSCH may beconfigured per CORESET or per each search space set or per each DCIformat or per each DCI size. In each CORESET or per DCI format, a set ofpatterns which may be indicated in time-domain resource allocation fieldmay be configured. For example, Table 5 shows an example ofconfiguration for PDSCH scheduling.

TABLE 5 Number Index of slot Start-End OFDM symbol 1 1 1^(st) OFDMsymbol - end of DL-centric 2 1 1^(st) OFDM symbol - end of slot 3 21^(st) OFDM symbol - end of DL centric in first slot, first DM-RS OFDMsymbol - end of slot in second slot 4 2 1^(st) OFDM symbol - end of DLcentric in first slot, 1^(st) OFDM symbol - end of slot in second slot 52 1^(st) OFDM symbol - end of slot in first slot, 1^(st) OFDM symbol -end of slot in second slot 6 2 1^(st) OFDM symbol - end of slot in firstslot, first DM-RS OFDM symbol - end of DL centric in second slot 7 4 DLportion indicated in slot format indicator index 1 8 4 DL portionindicated in slot format indicator index 5

When this is configured to a CORESET, DCI from the CORESET may indicate1, 2 or 4 slot aggregations starting from the same slot where the DCI istransmitted. Alternatively, additional offset in terms of slot may beindicated to support cross-slot scheduling and multi-slot aggregation.To also support cross-slot scheduling, cross-slot scheduling may be alsoindicated as one of pattern for data mapping. Or, separate field may beused for cross-slot scheduling. Alternatively, either cross-slot ormulti-slot aggregation may be used where different entries may beapplied depending on cross-slot or multi-slot scheduling. In theconfiguration, the field size for time-domain resource allocation may beimplicitly indicated, depending on the number of entries in theconfigured table. Or, the field size for time-domain resource allocationmay be explicitly indicated. If the number is smaller than the number ofentries in the configured table, the first entries indictable by thefield may be used.

Multi-slot based scheduling and cross-slot based scheduling isdescribed. As mentioned above, multi-slot based scheduling or cross-slotbased scheduling may be indicated by at least one of the followingoptions.

(1) Explicit indication of start OFDM symbol and/or end OFDM symbol ineach slot: Maximum number of slots which is schedulable may beconfigured, and the maximum number of slots may define the field size.Also, the number of possible candidates in each slot may be predefinedor higher layer configured. If the number of possible candidates is K,log 2K bits are necessary for each slot. Therefore, the field size maybecome log 2K*m, where m is the maximum number of slots indictable bycross-slot based scheduling or multi-slot based scheduling. Cross-slotbased scheduling and multi-slot based scheduling may utilize the unifiedfield, and for cross-slot scheduling, one entry in each slot may be setas NULL. Alternatively, for cross slot based scheduling, offset fieldmay be separately used or one slot indication (e.g. current slotindication) may be used for the offset of slot.

When mini-slot based scheduling is used, similar mechanism may be used.Alternatively, when mini-slot based scheduling is used, indication ofstart OFDM symbol within a slot and duration may be indicated byresource allocation mechanism of contiguous time-domain resource. Or,the number of multi-mini-slots may be explicitly indicated, as aseparate field with start+duration for mini-slot based scheduling isindicated by contiguous time-domain resource allocation. Formulti-mini-slot based scheduling, the same size of data duration may beused over multiple mini-slots contiguously. Alternatively, anotherapproach for indicating cross-slot based scheduling and multi-slot basedscheduling is to indicate slot number, which can be used for cross-slotbased scheduling, the offset between PDCCH and PDSCH (or PUSCH), thenumber of slot aggregation for multi-slot based scheduling, andtime-domain resource allocation in a slot. In case of cross-slot basedscheduling, only one slot may be scheduled, and in case of multi-slotbased scheduling, time-domain resource allocation may be repeated.

(2) DCI field for cross-slot based scheduling and multi-slot basedscheduling may be different. The DCI field for cross-slot basedscheduling may include an offset to start cross-slot scheduling data,and time-domain resource allocation which may be restricted only to aslot. In case of multi-slot based scheduling, different resourceallocation mechanisms mentioned above may be used.

Table 6 shows options for DCI field for multi-slot based scheduling andcross-slot based scheduling.

TABLE 6 Multi-slot & Size of DCI Same-slot & Cross-slot & starting inthe Cross-slot & field single slot single slot same slot multi-slot Ceil(log₂K) * Unused slots can Unused slots can Unused slots can Unusedslots can m(e.g. m = 4, be indicated be indicated be indicated beindicated K = 5) with NULL with NULL with NULL with NULL e.g. [2 1 1 1](1^(st) e.g. [1 1 3 1] (3^(rd) e.g. [2 4 5 5] (4 e.g. [1 1 3 4] (3^(rd)slot scheduling slot scheduling slot aggregation & 4^(th) slot withDwPTS with full DL) with excluding scheduling with length) data mappingat full DLs) control region in non-scheduled slots) Ceil (log₂K * Unusedslots can Unused slots can Unused slots can Unused slots can m)(every Kbe indicated be indicated be indicated be indicated states are used withNULL with NULL with NULL with NULL for each slot) -> similar to theabove approach with reduced number of bits Ceil (log₂m) + Number of slot= Number of slot = Number of slot = Not supported ceil (log2K) 1, timedomain offset to aggregated -> Assume time- resource can be PDSCH, timeslot #, time domain resource one from K domain resource domain resourceis repeated over entries in the slot repeated over multiple slots e.g.[1] + [3] e.g. [2] + [3] aggregated slots (2^(nd) slot e.g. [3] + [5] (3scheduled with slots full DL) aggregation with DwPTS mapping) Fieldindicated Only time- Time-offset + Time-domain Offset + time- betweensame, domain resource one-slot time- resource domain resourcecross-slot, multi- for a slot domain RA allocation of allocation of slotscheduling + multiple slots + multiple slots + separate field number ofslots number of slots (DCI field size aggregated (may aggregated (maycan vary) be implicit) be implicit) Index from a Index from a Index froma Index from a Index from a table which table table table table includesentries of same-slot, cross-slot, multi- slot scheduling with datadurations

Table 7 shows examples of K entries in each slot scheduling for PDSCH.

TABLE 7 1 NULL 2 1^(st) symbol - end of DL centric slot (the end symbolof DL centric slot is indicated to the UE by configuring UpPTS region +UE-specific gap 3 1^(st) symbol - end of slot 4 Next symbol to the firstDM-RS (or same symbol to DM-RS if data/DM-RS multiplexing is allowed) -end of slot 5 Next symbol to the first DM-RS (or same symbol to DM-RS ifdata/DM-RS multiplexing is allowed) - end of DwPTS

For the fifth approach mentioned above in Table 6, i.e. index from atable which includes entries of same-slot, cross-slot, multi-slotscheduling with data durations is used, the table should be defined.Table 8 shows an example of the table including entries of same-slot,cross-slot, multi-slot scheduling with data durations.

TABLE 8 Number Start slot Index of slot index Start-End OFDM symbol 1 1Same as 1^(st) OFDM symbol - end of DL-centric PDCCH 2 1 Same as 1^(st)OFDM symbol - end of slot PDCCH 3 2 Same as 1^(st) OFDM symbol - end ofDL centric in first PDCCH slot, first DM-RS OFDM symbol - end of slot insecond slot 4 2 Same as 1^(st) OFDM symbol - end of DL centric in firstPDCCH slot, 1^(st) OFDM symbol - end of slot in second slot 5 2 Same as1^(st) OFDM symbol - end of slot in first slot, PDCCH 1^(st) OFDMsymbol - end of slot in second slot 6 2 Same as 1^(st) OFDM symbol - endof slot in first slot, PDCCH first DM-RS OFDM symbol - end of DL centricin second slot 7 4 Same as DL portion indicated in slot format indicatorPDCCH index 1 8 4 Same as DL portion indicated in slot format indicatorPDCCH index 5 9 1 In the 1^(st) OFDM symbol - end of DL-centric nextslot 10 1 In the 1^(st) OFDM symbol - end of slot next slot 11 1 In 2slots 1^(st) OFDM symbol - end of DL-centric afterwards 12 1 In 2 slots1^(st) OFDM symbol - end of slot afterwards 13 2 In the 1^(st) OFDMsymbol - end of slot in first slot, next slot 1^(st) OFDM symbol - endof slot in second slot 14 2 In the 1^(st) OFDM symbol - end of slot infirst slot, next slot first DM-RS OFDM symbol - end of DL centric insecond slot 15 4 In the DL portion indicated in slot format indicatornext slot index 1 16 4 In the DL portion indicated in slot formatindicator next slot index 5

Referring to Table 8, number of slots, start slot index and/or start-endOFDM symbol are indicated by the index. Even though it is described thatall of number of slots, start slot index and/or start-end OFDM symbolare indicated by the index in Table 8, at least one of combination ofnumber of slots, start slot index and/or start-end OFDM symbol may beindicated by the index. The index may be provided by the time domainresource assignment field of the DCI.

Furthermore, similar mechanism may be also applied to PUSCH. Onlydifference is that default offset may be added to the table in PUSCHscheduling. The default offset may be configured by higher layer forslot based scheduling. For example, if the default offset is configuredas 1 slot, actual scheduling may occur in the slot indicated by DCI+1slot. For PDSCH, the default offset may be zero. If there is noconfiguration for UL, the default offset may be zero.

2. Cross-BWP Scheduling/Cross-Carrier Scheduling

When cross-BWP or cross-carrier scheduling is used, for determining oftiming to start and end for PDSCH or PUSCH, the following approaches maybe considered.

(1) Start position and end position for PDSCH or PUSCH indicated in DCIfield may be interpreted based on the slot for PDSCH or PUSCH. In thiscase, it may be assumed that start slot overlaps with the (first orentire or last) OFDM symbol(s) scheduling DCI. Or, it may be assumedthat the first slot overlaps with a slot in the scheduling carriercontaining scheduling DCI. The start slot may be the slot of PDSCH orPUSCH that overlaps with the first OFDM symbol of PDCCH. Or, the startslot may be the slot of PDSCH or PUSCH that overlaps with the CORESETtransmitting scheduling DCI. Or, the next slot of a slot which overlapswith the first OFDM symbol of scheduling DCI or PDCCH may be the firstslot for data scheduling. Alternatively, the slot which overlaps withthe last OFDM symbol of PDCCH or CORESET may be as the first slot fordata scheduling.

(2) Start position and end position for PDSCH or PUSCH may be explicitlyconfigured/indicated. Similar to start position indication of PDSCHscheduling in LTE, the start position in OFDM symbol or slot may beindicated. The offset may be applied to the start OFDM symbol or startslot which is determined by the overlapping with first or end of PDCCHcontaining DCI.

When cross-BWP scheduling or cross-carrier scheduling is used, fordetermining start OFDM symbol, if start OFDM symbol starts relative tothe start of the slot, it is necessary to determine the slot where startoffset is applied. Start slot may be defined as mentioned above. Ifthere are two slots which overlap with start or end of control OFDMsymbol (e.g. 15 kHz OFDM symbol and 120 kHz slot), either the first orsecond slot may be selected. Or, the slot with more overlapping portionmay be selected. If start offset is applied at the OFDM symbol ofcontrol channel (e.g. mini-slot based scheduling), the last or firstOFDM symbol of a carrier or BWP where PDSCH or PUSCH is scheduled to thecontrol channel OFDM symbol may be used for the reference.

When cross-carrier scheduling or cross-BWP scheduling is used, the ratematching pattern indication still may be used and the rate matchingpattern may be applied to the scheduled BWP or carrier. In this case, asthe UE may not be configured with CORESET in the scheduled BWP/carrier,the rate matching pattern may include the duration or the duration(possibly also the start OFDM symbol) for CORESETs may be alsoconfigured.

Cross-carrier scheduling may be configured per CORESET or per searchspace. For each CORESET or for each search space set configuration,cross-carrier scheduling may be enabled or disabled for a carrier.Alternatively, cross-carrier scheduling may be configured per RNTI. Ifcross-carrier scheduling configured per RNTI, all scheduling, e.g. forC-RNTI on a carrier, may be cross-carrier scheduled by another carrier.

In scheduling PUSCH, even with slot based scheduling, the start positionmay be determined as follows even with self-carrier or self-BWPscheduling.

(1) If PUSCH starts in the same slot where control channel istransmitted (and thus less than slot duration transmission), the startOFDM symbol may be defined as offset indicated by DCI+prefixed offset.The prefixed offset may be necessary to accommodate control decoding andpreparation processing for PUSCH transmission. Similar approach may alsobe applied to PUCCH transmission as well.

(2) If PUSCH starts in the start of slot, the default value for start ofPUSCH transmission may be the next slot after control channel istransmitted.

In other words, default offset value may be configured for determiningstart OFDM symbol for PUSCH. The default offset value may be eitherpredefined or higher layer configured.

When cross-carrier scheduling or cross-BWP scheduling is used, thedefault offset may be applied by determining either the last OFDM symbolwhich overlaps with the OFDM symbol used for control region or next slotafter control region. If two slots are overlapped with the controlregion, the latter slot may be the next slot instead of pushing it toanother slot. Alternatively, the slot which comes after the slot whichpartially or fully overlaps with control region may be the next slot.

3. Transport Block Size (TBS) Determination

With variable effective number of REs due to various RSs and/or ratematching patterns, TBS may be obtained based on a function. For example,a simple function for obtaining TBS may be defined by Equation 1.TBS=floor((M_re*Spectral efficiency*a number of allocatedRBs)/8)  [Equation 1]

When the function is used, there may be couple of considerations tohandle special packet size and variable number of effective REs due tovarious rate matching patterns. The followings may be considered.

(1) Special Packet Size Handling

-   -   A set of modulation and coding scheme (MCS) and RB pairs may be        reserved for special packet sizes. To support voice over        Internet protocol (VoIP) or emergency service, etc., in a set of        specific conditions such as a combination of MCS and number of        scheduled RBs in a slot based scheduling (excluding multi-slot        scheduling and mini-slot scheduling), a UE may use a TBS table        where special packet sizes are defined per combination.    -   A set of MCS values may be reserved for special packet sizes or        may refer to a TBS table. To allow flexible RB scheduling,        instead of selecting pairs between MCS/RBs, only a few values of        MCS may be reserved for special packet sizes.    -   Direct indication indicating whether to refer a table with        special packet sizes or use the function to obtain TBS may be        used. Whenever a UE is indicated with special packet sizes or        need to refer a TBS table instead of function, it may be        explicitly indicated by DCI. Unless otherwise indicated, a UE        may use the function.    -   A set of entries in MCS values may be reserved for special        packet sizes. These entries may be shared between retransmission        and indication of special packet sizes. For example, in case of        initial transmission, the set of reserved entries may be used        for special packet sizes. For the retransmission of special        packets, TBS may be known by initial transmission. Or, for the        retransmission of special packets the same TBS may be used based        on scheduling and TBS function. For retransmission cases, the        special entries may be used for changing modulation.

(2) DCI Indication for Obtaining TBS

-   -   Approach 1: MCS which represents spectral efficiency may be used        for scheduling, and MCS may consists of both modulation and        spectral efficiency    -   Approach 2: Modulation and spectral efficiency may be indicated        separately. A set of spectral efficiency may be different per        modulation. Though it may be indicated jointly, the point is        that modulation order may be different per same spectral        efficiency value or per corresponding the same        signal-to-interference and noise ratio (SINR) range. This may        also be efficient if binary phase shift keying (BPSK)) is used,        particularly for UL. Furthermore, this may also be applied to        potential future adaptation of higher modulation order, such as        1024 quadrature amplitude modulation (QAM). The spectral        efficiency between QAM and BPSK may be similar in the range of        similar SINR, though BPSK may be selected for better        peak-to-average power ratio (PAPR) or power efficiency.    -   Approach 3: A set of mother MCS table which consists of        modulation and spectral efficiency may be pre-determined        specified in the specification. A UE may be configured with        start and end indices in the mother MCS table. The start and end        indices in the mother MCS table may be dynamically indicated        by DCI. Or, only a subset of entries may be selected from the        mother MCS table, and one of the selected/configured subset of        entries may be dynamically indicated by DCI.

When a UE is configured with overhead value, as the overhead value mayhave different impact depending on data duration, the followings may beconsidered.

-   -   The overhead may be scaled based on the duration of data. For        example, overhead may be computed as ceil (overhead*X/12), where        X is the duration of data.    -   The multiple values of overhead may be configured, and different        value may be selected depending on the range of data duration.        For example, overhead 1 and overhead 2 may be configured.        Overhead 1 may be applied between 1 to 6 OFDM symbols, and        Overhead 2 may be applied between 7 to 14 OFDM symbols.

4. DCI Sizes/Formats

For convenience, the following DCI formats may be defined in NR. Thefollowing DCI formats are only exemplary. Some DCI formats may beshared.

-   -   DCI format 0: DCI format used for scheduling remaining minimum        system information (RMSI), i.e. system information block type 1        (SIB1)    -   DCI format 1: DCI format used for scheduling random access        response (RAR)    -   DCI format 2: DCI format used for scheduling Msg 4, i.e.        contention resolution message in random access procedure    -   DCI format 3: DCI format used for scheduling PDSCH containing        RRC connection & configuration message    -   DCI format 4: DCI format used for scheduling UE-specific PDSCH        with transmission scheme and various features which is scheduled        in USS    -   DCI format 5: DCI format used for scheduling UE-specific PUSCH        with transmission scheme and various features which is scheduled        in USS    -   DCI format 6: DCI format used for scheduling UE-specific PDSCH        which is scheduled in CSS and/or fallback DCI    -   DCI format 7: DCI format used for scheduling UE-specific PUSCH        which is scheduled in CSS and/or fallback DCI    -   DCI format 8: DCI format used for group common DCI such as        transmit power control (TPC) commands    -   DCI format 9: DCI format used for puncturing indication    -   DCI format 10: DCI format used for slot formation indication

In NR with many features involving dynamic indication via DCI, it may benecessary to allow configurability of a certain set of fields dependingon the used features. In handling of various RRC reconfigurations withvarious features, it may be important to maintain constant DCI formatwhich is used for fallback DCI, such as DCI format 6 and format 7mentioned above. In this sense, Table 9 shows assumptions of differentfeatures for broadcast data by CSS, UE-specific data scheduling by USS,UE-specific scheduling by fallback DCI.

TABLE 9 Broadcast channel (RMSI, RAR, UE-specific data by Paging) USSFallback DCI Code block group Not supported UE-specifically Notsupported (CBG)-based enabled with the retransmission number of CBGsconfigured CBG flushing Not supported Configurable to be Not supportedindication (CBGFI) present Dynamic vs. semi- Single slot is Single slot,cross- Semi-statically fixed static time-domain assumed with only aslot, or multi-slots timing is assumed. resource few choices of can beenabled to (starting/duration) starting/duration dynamically indicateinformation combinations by DCI. Dynamic rate Time division Can beenabled by TDM between matching indicator multiplexing (TDM) higherlayer signaling control and data is (e.g., control-data between controland (e.g. configuration of assumed (thus not resource sharing) data isassumed (thus set of rate matching supported) not supported) patternsindictable by DCI) Subband precoding Not supported Fixed size for UL Notsupported matrix indicator grant if enabled (PMI) Quasi-collocatedAssume that control Can be enabled by Assume that control (QCL)information and data use the same higher layer to and data use the samerelated to data beam dynamically indicate beam for DL. reception(control- QCL information for Assume data different beam datacorresponding beam support) reception/transmission to the beam used forcontrol transmission is used for PUSCH Bandwidth and BWP Bandwidth ofdefault UE-specifically Depends on fallback assumed for BWP and defaultactivated DL/UL mechanism of active frequency resource BWP BWP is usedBWP switching. allocation respectively for PDSCH and PUSCH Resourceblock Predefined RBG size can be Predefined, or group (RBG) configuredper each configured before or information BWP to align during RRCbetween narrowband connection procedure and wideband UEs, RBG sizes canbe also dynamically changed via DCI

According to assumptions described in Table 9, the followings may beconsidered in detail.

(1) CBG-based retransmission: CBG-based retransmission may not be usedfor DCI scheduling broadcast data or fallback DCI. If CBG-basedretransmission is used, the number of CBG may be configured bycell-specific signaling, such as RMSI.

(2) Indication of start and duration of data (i.e. dynamic schedulingtiming and duration):

For broadcast channel where beam sweeping is expected, the followingsmay be indicated for start and duration of data, if FDM between SS blockand data is supported.

-   -   00: start at OFDM symbol after CORESET, end at end of DwPTS,    -   01: same as 1st SS block in the slot,    -   10: same as 2nd SS block in the slot,    -   11: start at DM-RS symbol position of the next slot, end at end        of DwPTS of the next slot

When multi-beam is not used, 00 may be used as a default value.

For unicast scheduling via USS, DCI field may support only one ofsingle/same-slot, single/cross-slot, multi-slot/same-slot,multi-slot/cross-slot at a time by higher layer configuration. Ordynamic switching among those may be supported as well. Regardless ofwhich option is used, it may be necessary that a UE is configured withthe maximum number of slots which can be referred from DCI. For example,a UE may be configured with maximum number of slots schedulable formulti-slot aggregation or maximum number of slot used for cross-slotscheduling gap.

For fallback DCI, for a simplicity, single slot and same slot schedulingmay be used for PDSCH, and single slot and cross-slot with fixed gap maybe used for PUSCH.

(3) BWP Assumption for Each Scheduling DCI

It is natural to assume that default BWP is used for broadcastscheduling. The default BWP may be reconfigured if it is different fromBWP covering bandwidth for RMSI scheduling. Frequency and bandwidth ofdefault UL BWP may be indicated by RMSI. For example, frequency regionaround physical random access channel (PRACH) configuration within UEminimum transmitting bandwidth may be defined as the default UL BWP.Default UL BWP may be used for Msg 3 scheduling and other UL scheduling,until a UE is reconfigured with UE-specific active UL BWP. Also, it isnatural to assume that UE-specifically activated BWP is used for unicastscheduling.

In terms of BWP for fallback DCI, it may depend on fallback mechanism ofactive BWP switching and (re) configuration of BWPs. If the networkensures fallback by transmitting duplicate DCI and data in both BWPs(old and new active BWP), fallback DCI may be located in UE-specificallyactive BWP, at least for DL. However for UL, it may become challenging.Thus, it may be necessary to define fallback BWP at least for UL, whichmay be used for fallback DCI scheduling. Fallback BWP may be same asdefault BWP.

With potential DCI fields for various features, DCI sizes for each DCIformat may different from each other. Table 10 shows sizes of DCI format0 to DCI format 3.

TABLE 10 Field DCI Format 0 DCI Format 1 DCI Format 2 DCI Format 3 MCS MM M M Frequency Determined Determined Determined Determined Resourcebased on default based on default based on default based on defaultAllocation BWP BWP BWP BWP Time Resource T1 >0 at least in 0 if fixed or0 if fixed or 0 if fixed or Allocation multi-beam semi-staticallysemi-statically semi-statically scenario fixed value is fixed value isfixed value is used and assume used and assume used and assume singleslot single slot single slot scheduling scheduling scheduling NDI 1 1 11 Hybrid 0 if default 0 if default 0 if default K1 automatic repeat HARQprocess HARQ process HARQ process request (HARQ) ID is fixed ID is fixedID is fixed process ID Redundancy N N N N Version TPC N/A N/A P bits Pbits HARQ-ACK N/A N/A S S resource Beam direction 0 assuming 0 assuming0 assuming 0 assuming for PD/USCH same beam same beam same beam samebeam (QCL direction direction direction direction indication) betweencontrol between control between control between control and data anddata and data and data MIMO related 0 assuming 0 assuming 0 assuming 0assuming parameters (e.g., fixed or semi- fixed or semi- fixed or semi-fixed or semi- antenna port, # statically statically staticallystatically layers, configured value configured value configured valueconfigured value scrambling) is used is used is used is used Flag for TBN/A N/A N/A N/A based or CBG based HARQ- ACK (if configured) Flag forN/A N/A N/A N/A Flushing CBG bitmap for N/A N/A N/A N/A retransmission #of subbands & N/A N/A N/A N/A subband PMIs for UL grant

Table 11 shows sizes of DCI format 4 to DCI format 7.

TABLE 11 DCI Format 4 DCI Format 5 DCI Format 6 DCI Format 7 Field (DLDCI USS) (UL DCI USS) (DL DCI CSS) (UL DCI CSS) MCS M M M M FrequencyDetermined Determined Determined Determined Resource based on activebased on active based on active based on active Allocation DL BWP UL BWPDL BWP DL BWP Time Resource T2 T3 0 if fixed or 0 if fixed or Allocationsemi-statically semi-statically fixed value is fixed value is used andassume used and assume single slot single slot scheduling scheduling NDI1 1 1 1 HARQ process K2 K3 K1 K1 ID Redundancy N N N N Version TPC P P PP HARQ-ACK S N/A S N/A resource Beam direction B1 B2 0 assuming 0assuming for PD/USCH same beam same beam (QCL direction directionindication) between control between control and data and data MIMOrelated Q1 Q2 0 0 parameters (e.g., antenna port, # layers, scrambling)Flag for TB 1 1 0 0 based or CBG based HARQ- ACK (if configured) Flagfor 1 1 1 1 Flushing CBG bitmap for Y Y Y Y retransmission # of subbands& N/A Z 0 0 subband PMIs for UL grant

Referring to Tables 10 and 11, the required DCI size for DCI formats mayvary depending on the applicability of various features, such as dynamicindication of start/end of data, subband PMI, beam related information,MIMO information, etc. Meanwhile, actual bit size for DCI formats may bedifferent by jointly combining some fields or creating more DCI formats.

Based on the above observations, the followings may be considered.

(1) At least one DCI size X, which may be used to schedule broadcastchannels such as RMSI, paging, on-demand system information (OSI), etc.,may be defined.

(2) Fallback DCI may use DCI size X used to schedule broadcast channels.

(3) A UE may be semi-statically configured with a set of DCI fields (orfeatures to be indicated dynamically), which defines necessary DCIformat(s).

(4) The number of DCI sizes that a UE needs to monitor at a time shouldbe minimized.

-   -   DCI sizes between DCIs of TB based scheduling and CBG based        scheduling may be same to minimize the overhead. DCI format can        be different between two.    -   The DCI size between DL scheduling DCI and UL grant DCI should        be kept as same, as long as the padding is not significant. If        padding overhead is significant, separating search space between        two DCIs may be considered.

Handling various DCI formats with different features is described. Withvarious features which may be configured explicitly or implicitly byhigher layer, such as CBG based retransmission, dynamic indication ofstart/duration of data, flushing indication, cross-numerology orcross-BWP scheduling, cross-carrier scheduling, etc., various DCI sizesmay be needed for a UE to support. In order to minimize the UE blinddecoding, the following approaches may be considered.

(1) Approach 1: Single DCI size may be configured by higher layer (i.e.RRC layer) and size of fallback DCI may be prefixed. That is, the sizeof fallback DCI size does not change by RRC configuration. The defaultconfigurations for various optional features may be used for fallbackDCI, and the size of the fallback DCI is not changed by RRCconfiguration. The drawback of this approach is that if the networkwants to dynamically switch between two features, the overhead may beincreased as the DCI needs to include fields related to both features(or both set of features).

(2) Approach 2: Multiple DCI sizes or formats may be configureddepending on the enabled features, and a UE may be configured with K DCIsizes. Depending on the combinations of enabled features, a UE may beconfigured with possible set of DCI format(s) or DCI sizes or DCIcombinations. For example, a first DCI format may include CBG basedretransmission and dynamic indication of start/duration. A second DCIformat may include CBG based retransmission, dynamic indication ofstart/duration and cross-BWP or cross-carrier scheduling. A third DCIformat may not include all features which can be configured by higherlayer. A UE may be configured with a set of DCI formats for each DL andUL, respectively. Then, a UE may be also configured with a set of DCIsizes that the UE can utilize per each CORESET monitoring. For example,a UE may be configured with first DCI size, second DCI size, and thirdDCI size. Then, if the UE is configured with three CORESETs, firstCORESET may be configured with first DCI size & second DCI size, secondCORESET may be configure with third DCI size, and the third CORESET maybe configured with only second DCI size. For each DCI size, a UE mayalso be configured with which format(s) are mapped with appropriatepadding.

If this approach is used, necessary indication of DCI format may beincluded in DCI format respectively. The necessary indication of DCIformat may include DCI format index. Furthermore, if separate index isnot used between DL/UL, the necessary indication of DCI format mayinclude separation between DL and UL scheduling DCI.

If this approach is used, to support fallback DCI, it may be necessaryto define fallback DCI size as well. The size of fallback DCI may bepredefined or may be determined configurations by RMSI. Somequantization on default fallback DCI size may also be considered, orexplicit configuration of fallback DCI size may be configured by theRMSI or OSI or PBCH.

For separating or supporting more than one DCI sizes for USS, CBG-basedretransmission and TB based transmission may be supported, particularlywhen CBG-based retransmission size is large. Alternatively, ULsubband-PMI may be supported.

Alternatively, instead of configuring of DCI sizes explicitly, a certainDCI format may be configured as reference. In other words, DCI formatsmay be grouped, and the size of DCI formats in the group may bedetermined by the reference DCI format in the group. For example, DCIformat 1 & 2 may be grouped, and size of DCI format 2 may be determinedby DCI format 1 which is a reference DCI format in the group. Foranother example, DCI format 1, 2 and 3 may be grouped, and size of DCIformats 2 and 2 may be determined by DCI format 3 which is a referenceDCI format in the group. In other words, a set of groups of DCI formatsmay be defined with a reference DCI format per each group. The DCI sizeor reference DCI format may be implicitly defined by the largest payloadDCI format among DCI formats in the group.

FIG. 9 shows an example of relationship between various features, DL DCIformats, UL DCI formats, size of DCI formats and CORESET according to anembodiment of the present invention. Referring to FIG. 9, for example,DL DCI format 1 includes information on CBG-based retransmission,information on dynamic indication of start/duration, information onmandatory features (or default features), and information on number ofHARQ process adaptation. DL DCI format has a size 2, and is mapped toCORESET 1. On the other hand, DL DCI format 0, which is fallback DCI,only includes information on mandatory features (or default features).DL DCI format 0 has size 0, and is mapped to CORESET 2.

There may be multiple DCI formats for scheduling broadcast channels,such as RMSI, paging, RAR, etc. Each format may be expected to beaccessed in different search space, and each search space may or may notshare the same CORESET. If there is no explicit configuration, defaultbehavior may be to share the same CORESET configured for RMSI for otherbroadcast channels. In such case, it may be desirable to align sizes forDCIs scheduling broadcast channel. Furthermore, there may be multiplegroup common DCIs, such as group common PDCCH, group common TPCcommands, group common HARQ-ACK. Each group common DCI may be treated asa single DCI format, and size of group common DCI may be aligned withdifferent DCI formats, following the description mentioned above.

In summary, the present invention proposes the followings for DCIsizes/formats.

-   -   A set of DCI formats may be defined and/or configured based on        enabled features by the UE or cell-specific higher layer        signaling.    -   A set of groups for DCI formats may be defined, and DCI formats        in each group may have a single size. The single size for DCI        formats may be defined by configuring a set of DCI sizes or a        set of DCI formats in each group. The single size for DCI format        for each group may be either explicitly configured or determined        based on a reference DCI format or determined based on the        largest DCI size among DCI formats in the group.    -   For each group, a UE may be also configured with one or more        CORESET(s), and the UE may be supposed to monitor the given        group. Within each group (i.e. DCI format group), DCI format        indicator may be configured to differentiate different DCI        formats. A size of DCI format indicator may be added to the size        of DCI for each group. For example, if the group has two DCI        formats, a size of DCI format indicator bit may be 1 bit, and if        the group has three DCI formats, a size of DCI format the        indicator bit is 2 bits. Alternatively, the size of the DCI        format indicator may also be configured per each group or may be        defined by the maximum possible number of DCI formats belonging        to the group. At least for the group containing default or        fallback DCI, it may be necessary to have prefixed DCI format        indicator. Only DL and UL may be separated by single bit, and        other DCI formats may be differentiated by RNTI.

If the DCI format indicator is used, there may be no need of separatingRNTI per different broadcast channel such as RMSI, paging, and RAR.Instead, different RNTIs may be used per transmission/reception point(TRP). In other words, RNTI value may be same for DCI formats having thesame size, and the DCI format indicator may differentiate the purpose orthe scheduling target of the DCI. For example, it may be assumed thatDCI format 0 is used for RMSI, DCI format 1 is used for paging, DCIformat 2 is used for RAR, and DCI format 3 is used for Msg 4. This mayincrease the overhead of DCI, however. So, the necessary number of RNTIsreserved for broadcast channel may be reduced by the DCI formatindicator.

-   -   For each DCI format in the group, the number of blind decodings        per each aggregation level may also be configured. Even with the        same CORESET, different number of blind decodings may be        allocated to different DCI format. However, for the simplicity,        a size of DCI formats for each group may be same regardless of        separate blind decoding configurations per DCI format.    -   There may be a default DCI format group which contains        fallback DCI. The fallback DCI may be configured by RMSI or may        be prefixed. As the fallback DCI may be shared with CORESET for        RMSI, the size of the fallback DCI may be defined by PBCH, if        the size of scheduling RMSI is not be used for the size of the        default DCI format group. In other words, the default DCI format        group with fixed size, which may be configured by PBCH or RMSI        or predefined, carrying at least fallback DCI(s) may be defined.

At least CORESET for group common PDCCH, UE-specific scheduling, RACHprocedures, etc., may be configured per each configured BWP. Dependingon UE capability and the network operation, a UE may be configured withonly one BWP or multiple BWPs. Thus, DCI design should consider bothcases.

There are at least the following CORESETs configured to a UE.

(1) RMSI CORESET: This may be shared with other OSI, RAR/Msg 4 andUE-specific scheduling.

(2) RAR/Msg 4 CORESET

(3) UE-specifically configured CORESET

(4) CORESET for CSS configured separately for each configured BWP (e.g.for group common DCI)

As different DCI sizes may potentially lead increased blind decoding ofcontrol channels, at least the following aspects needs to be clarifiedin order to determine DCI sizes.

-   -   Which features can be enabled in the monitored DCI in a        combination of {CORESET, a search space type, RNTI}?    -   What is the resource allocation type for both time/frequency        domain, and bandwidth for frequency domain, maximum        duration/slots for time domain?

Table 12 shows an example of DCI formats/main features/frequencybandwidth and/or time domain resource allocation for each CORESET/SStype and RNTI.

TABLE 12 Time domain CORESET, SS resource type, RNTI DCI formats Mainfeatures Frequency BW allocation RMSI Same as fallback Same as fallbackInitial DL/UL Following CORESET, DCI DCI BWP predefined table CSS,{SI-RNTI, RAR-RNTI, Temp-C-RNTI, C-RNTI} RMSI Same as fallback Same asfallback Initial DL/UL Following CORESET, DCI DCI BWP predefined tableUSS, {C-RNTI} RAR Same as fallback Same as fallback Initial DL/ULFollowing CORESET, DCI DCI BWP predefined table CSS, {RAR- RNTI, Temp-C-RNTI, C-RNTI} UE-specific Same as fallback Same as fallback ConfiguredBW, Following CORESET, DCI DCI which can be predefined table CSS,{C-RNTI} different from UE-specific BWP's BW UE-specific TM-DCI-Configured Configured Following CORESET, format, fallback features,BWP's BW configured table USS, {C-RNTI} DCI fallback DCI features

Referring to Table 12, DCI format scheduling RMSI, OSI, RAR and Msg 4 issame as DCI format for fallback DCI. Furthermore, a frequency domainbandwidth which can be scheduled by a DCI in CSS of RMSI CORESET isdefined by initial DL and UL BWP.

To handle various DCI format(s) with various features configured to aUE, mechanisms to reduce the number of DCI sizes at a given time shouldbe considered. Generally, the followings may be considered.

(1) Approach 1: Maximum DCI size which can cover the necessary DCIformats with potentially DCI format may be configured. AUE may interpretthe DCI contents differently depending on DCI format. Two DCI sizes maybe defined, one which is for fallback DCI and the other for UE-specificscheduling DCI. By this approach, DL/UL scheduling DCI sizes may bealigned by necessary padding, and the maximum DCI size may be determinedbased on configuration of various features.

(2) Approach 2: DCI formats with similar DCI sizes may be grouped andeach CORESET may be configured with one or more of grouped DCI formats.For example, four DCI groups may be defined. A first DCI group mayinclude compact DCIs for group common DCI/PDCCH, a second DCI group mayinclude fallback DCI for DL/UL and DCIs for broadcast channels, a thirdDCI group may include DCIs for UE-specific PDSCH scheduling(transmission mode (TM) version), and a fourth DCI group may includeDCIs for UE-specific PUSCH scheduling (TM version). Each CORESET may beconfigured with different DCI groups. Instead of configuration ofdifferent set per CORESET, separate search space may also be considered.

(3) Approach 3: A CORESET may be configured with one or two DCI sizes.Each DCI size may also be configured with DCI format(s). The configuredDCI format(s) may use the configured/same DCI size by necessary padding.

(4) Approach 4: Separate transmission of DCI format with DCI payload maybe configured. Each DCI format may indicate the necessary DCI size.

Table 13 shows potential benefits and drawbacks of each approachmentioned above.

TABLE 13 Benefits Drawbacks Approach 1: Utilize A UE needs to support Incase the discrepancy between the maximum DCI size only a few DCI sizesmaximum sized DCI Format and the commonly regardless of various smallerDCI formats, padding overhead configurations in terms can be increased.of CORESETs and features. Approach 2: Utilize Padding overhead can Itmay impose scheduling constraints multiple DCI sizes with be reduced.where some DCI format(s) may not be grouping of DCI schedulable in allCORESETs or some formats partitioning of search space or CORESET amongdifferent DCI formats is necessary. Approach 3: Network Based on theHandling of fallback and broadcast is configuration betweenconfiguration, it can necessary which needs to work without DCI size andDCI achieve benefits of configuration. For that, at least one format(s)Approach 1 and 2. DCI size for fallback and broadcast channels seemsnecessary. Approach 4: Separate Padding overhead can It is complicatedto design separate DCI formation be reduced. coding between DCI fields,and also, indication search space and DCI mapping.

Based on the above observations, approach 3 may be preferred. That is,to minimize the number of DCI sizes that a UE needs to monitor at atime, a network may configure one or two DCI sizes per CORESET. For eachsize, one or more DCI format(s) may be mapped. For the DCI format(s)mapped to the same DCI size may use padding to align the DCI size. Foreach DCI size, additional field may be used to differentiate DCIformat(s) sharing the same size, if there are multiple DCI formats. Asize of fallback DCI and DCI for broadcast channels may be predefined,or may be computed without RRC signaling. For a CORESET where the UEmonitors fallback DCI and/or broadcast channels, one of the configuredDCI size may be same as size for fallback DCI and DCI for broadcastchannels.

5. Aperiodic Channel State Information (CSI) Support in DCI

In NR, aperiodic CSI on PUCCH may be supported as well in addition toaperiodic CSI on PUSCH. The main benefits of aperiodic CSI on PUCCH isfaster and shorter transmission of CSI by utilizing short PUCCH designcompared to PUSCH. Aperiodic CSI on PUCCH may be supported on shortPUCCH only. Aperiodic CSI on PUCCH may be a complementary and optionalfeature in addition to aperiodic CSI on PUSCH. Aperiodic CSI on PUCCHmay be triggered by utilizing existing DCI format/fields and byminimizing specification impacts.

As mentioned above, aperiodic CSI on PUCCH may be supported only onshort PUCCH. In that case, depending on UE geometry or needed coverage,it is possible that aperiodic CSI on PUCCH cannot be triggered eventhough aperiodic CSI on PUCCH is configured. In this case, it may seemwasteful to have a separate field in DL DCI for triggering aperiodic CSIon PUCCH. Furthermore, aperiodic CSI on PUCCH and aperiodic CSI on PUSCHmay not be triggered simultaneously. It is more desirable that eitherone is triggered depending on the necessity. Therefore, combiningaperiodic CSI trigger in one DCI may be preferable regardless whetherthe CSI is transmitted on PUCCH or PUSCH. Thus, aperiodic CSI trigger inUL grant may be reused for triggering aperiodic CSI on PUCCH. Morespecifically, a CSI request field in UE-specific UL-related DCI maytrigger a CSI report on PUCCH. If PUCCH or PUSCH is used for CSIreporting, it may be indicated in the CSI report setting.

When aperiodic CSI on PUCCH is triggered in UL grant, how to determinePUCCH resources in time-domain should be further clarified. In UL grant,indicating starting of PUSCH transmission may be indicated dynamicallyor based on semi-static configuration. To determine time domaininformation for PUCCH and PUSCH scheduled by one UL grant, the followingoptions may be considered.

(1) Option 1: Aperiodic CSI on PUCCH may be transmitted right before thescheduled PUSCH. For example, if PUSCH is scheduled between OFDM symbols5-11, aperiodic CSI on PUCCH may be scheduled at OFDM symbol 4 (if 1symbol PUCCH is configured).

(2) Option 2: Aperiodic CSI on PUCCH may be transmitted at the indicatedstart OFDM symbol for PUSCH. That is, PUSCH transmission starts afteraperiodic CSI on PUCCH transmission is completed. For example, if PUSCHis scheduled between OFDM symbols 5-11, and aperiodic CSI on PUCCH isscheduled at OFDM symbol 5 (if 1 symbol PUCCH is configured), PUSCHtransmission occurs between OFDM symbols 6-11.

(3) Option 3: Aperiodic CSI on PUCCH may be transmitted right after thescheduled PUSCH. That is, aperiodic CSI on PUCCH transmission startsafter PUSCH transmission is completed. For example, if PUSCH isscheduled between OFDM symbols 5-11, aperiodic CSI on PUCCH may bescheduled at OFDM symbol 12 (if 1 symbol PUCCH is configured).

(4) Option 4: Aperiodic CSI on PUCCH may be transmitted at the end OFDMsymbols of the scheduled PUSCH. For example, if PUSCH is scheduledbetween OFDM symbols 5-11, aperiodic CSI on PUCCH may be scheduled atOFDM symbol 11 (if 1 symbol PUCCH is configured), and PUSCH occursbetween 5-10.

(5) Option 5: Time domain information for aperiodic CSI on PUCCH may beconfigured in report configuration within a slot, and the time domaininformation may be used for PUCCH. PUSCH transmission may not occur inthe same OFDM symbol where PUCCH is transmitted. This may be realized bydynamic scheduling or PUSCH may be rate matched on the OFDM symbolswhere PUCCH is transmitted.

It should be further studied whether short PUCCH can be located in anyOFDM symbol when slot based scheduling is used. Some of options may notbe available in some situations. In that case, the benefits of aperiodicCSI on PUCCH may be very limited. Accordingly, it may be preferable toconfigure the time domain information of aperiodic CSI on PUCCH. Inother words, option 5 mentioned above may be adopted regardless of shortPUCCH design. If short PUCCH is allowed in any OFDM symbol, option 2 maybe adopted to maximize the benefits of aperiodic CSI on PUCCH. Insummary, UL-grant may carry aperiodic CSI trigger regardless ofcontainer (i.e. PUCCH or PUSCH). In UL-grant carrying trigger onaperiodic CSI on PUCCH, time domain information on short PUCCH may bedetermined by report configuration semi-statically or may be determinedbased on the location of scheduled PUSCH if short PUCCH can betransmitted in any OFDM symbols.

Alternatively, which option is used for aperiodic CSI on PUCCH may beconfigured in report configuration. Alternatively, aperiodic CSI onPUCCH may not be triggered with uplink shared channel (UL-SCH). In otherwords, when aperiodic CSI on PUCCH is triggered, PUSCH may not bescheduled. Furthermore, aperiodic CSI on PUCCH may be triggered with orwithout UL-SCH. In this case, resource allocation field may be set aszero or set as a predefined value. Or, a set of DCI fields may be set asa predefined value to indicate no resource allocation for PUSCH infrequency domain. Time domain resource allocation may be used for PUCCHtime domain information, and PUSCH will not be scheduled. In otherwords, aperiodic CSI without UL-SCH may also be triggered by UL granteven when aperiodic CSI on PUCCH is triggered.

When option 1 is used where DL grant is used for aperiodic CSI trigger,similar approach may be considered. That is, aperiodic CSI may betriggered without downlink shared channel (DL-SCH) transmission. Similarto UL grant without UL-SCH or PUSCH, a set of predefined value may beused for a set of DCI fields. Or, a resource allocation field may be setto a predefined value.

Furthermore, when option 1 is used, it needs to be clarified thatwhether HARQ-ACK and CSI will always be combined or not. If HARQ-ACK andCSI will be combined and PUCCH format for HARQ-ACK is indicateddifferently, the benefits of aperiodic CSI on PUCCH may be limited.Thus, aperiodic CSI trigger may transmitted only in DL grant. If thereis scheduled data, CSI and HARQ-ACK may be combined in PUCCH, and CSIand HARQ-ACK simultaneous transmission flag may be enabled. Depending onPUCCH format/resource configuration, aperiodic CSI may also betransmitted. In other words, this may be similar as periodic CSI. WhenPUCCH format does not carry all information due to limited resource, itis possible to drop some of aperiodic CSI contents.

When option 1 is used, PUCCH format carrying more than 2 bits may beused, and SR may also be carried jointly if SR is triggered.

When option 1 is used, and more than one PUCCH resources collidepartially or fully, aperiodic CSI on PUCCH may be considered as thehigher priority than periodic CSI, semi-persistent CSI and/or soundingreference signal (SRS) (including aperiodic SRS), but may be consideredas lower priority than HARQ-ACK/SR.

When HARQ-ACK is piggybacked to PUSCH due to non-simultaneoustransmission between PUCCH and PUSCH, aperiodic CSI on PUCCH also needsto be piggybacked on PUSCH. However, because aperiodic CSI on PUCCHneeds fast feedback and the network was able to trigger aperiodic CSI onPUSCH, if aperiodic CSI on PUCCH collides with PUSCH, aperiodic CSI onPUCCH may be dropped, instead of piggybacking on PUSCH. Particularly, incarrier aggregation (CA), when different numerology is used or differentlength between PUCCH and PUSCH is used, it may be desirable not topiggyback aperiodic CSI on PUCCH via PUSCH.

In other words, aperiodic CSI on PUCCH may be transmitted only via PUCCHin indicated resource. If the aperiodic CSI on PUCCH collides with otherdynamically scheduled resource (e.g. HARQ-ACK PUCCH resource or PUSCHresource), the aperiodic CSI on PUCCH may be dropped. When the aperiodicCSI on PUCCH collides with type 1 or type 2, the following approachesmay be considered.

-   -   Higher priority may be put on type 1 or type 2, and aperiodic        CSI may be dropped if type 1 and 2 is configured to have higher        priority over UL grant PUSCH or PUCCH.    -   For aperiodic CSI on PUSCH, priority between UL grant based        PUSCH and type 1/2 may be followed. For aperiodic CSI on PUCCH,        priority rule between PUCCH/CSI and type 1/2 may be followed.    -   Higher priority may always put on dynamically scheduled        including aperiodic CSI.    -   If piggyback on type 1 or 2 is allowed, aperiodic CSI may be        piggybacked. Otherwise, which one to drop may be determined        based on priority rule.

6. Fallback DCI

(1) Frequency Resource Allocation

When each BWP has CORESET configuration for CSS, the size of resourceallocation which can be indicated by CSS needs to be clarified. Thefollowing approaches may be considered.

-   -   Explicit indication of bandwidth & frequency location: Bandwidth        and frequency location of frequency resource allocation may be        indicated by the network per each BWP.    -   The same frequency region of configured CORESET for CSS may be        used for resource allocation as well. If CORESET configuration        is not contiguous, either the same dis-contiguous resource        allocation may be used (which may complicate resource        allocation) or the first and end of allocated CORESET may be        used to determine bandwidth and frequency location.    -   The same frequency/bandwidth resource may be used for initial        DL/UL BWP (at least resource allocation field size may be same        as initial DL/UL BWP) or default DL/UL BWP.    -   Regardless of CORESET configuration, the same bandwidth may be        used, and the start frequency may be same as the first PRB of        CORESET configuration. The bandwidth may be determined by the        configured resource allocation field size or the resource        allocation field size used in initial DL/UL BWP may be used.    -   Resource allocation for CSS may be based on the indicated        frequency/bandwidth. The indicated frequency/bandwidth may be        different from the configured DL or UL BWP.    -   If initial DL/UL BWP is also configured as one of BWP, or DL/UL        BWP may include initial DL/UL BWP, and the same CORESET to RMSI        CORESET is used in that BWP, the same DCI field/size to initial        DL/UL BWP may be used in such BWP.

(2) Time Domain Resource Allocation

For fallback DCI used in different BWP from initial DL/UL BWP, timedomain resource allocation field may also be configured. Wheninformation on time domain resource allocation is used, and a differentset of values are configured per each BWP, the timing value of scheduledBWP may always be used to apply the actual slot/resource fortransmission/reception of data.

7. Search Space Set and DCI Size Determination

Due to BWP adaptation and various DCI formats with different monitoringperiodicity, it needs to be clarified how the UE determines DCI size(s)monitored in one search space or across multiple search spaces. It alsoneeds to be clarified how the UE performs necessary padding to align thedetermined DCI size(s). In terms of DCI monitoring in PCell and/orprimary secondary cell (PSCell), the following cases may be considered.

(1) Case 1: Initial DL/UL BWP Before RRC Connection

Unless explicit search space set configuration is given, CORESET forRMSI may be used for scheduling RAR, Msg 4, UE-specific RRC messages,etc. In this case, search space set may be defined as the same set ofaggregation level & number candidates configured for RMSI or SI.Alternatively, for determining search space set, default monitoringperiodicity/offset may be defined as 1 slot. In other words, in everyslot, a UE may monitor the corresponding CORESET for Msg 4, UE-specificRRC messages. In other words, when USS is constructed, the sameconfiguration of set of {aggregation level, number of candidates} may beinherited, unless there is no explicit configuration. In terms ofmonitoring periodicity/search space, single slot with zero offset may beused until reconfigured. Alternatively, the first slot in every 1 ms maybe used as the default monitoring periodicity/offset.

Alternatively, search space set for RACH procedure, paging, OSI update,etc., may be configured separately. Regarding DCI size, the followingoptions may be considered.

-   -   Option 1: There may be only one DCI size per each configured        search space set. All DCI formats associated with RNTIs        configured with the same search space set may use the same DCI        size via padding. In this option, DCI format 1_0 (i.e.        fallback DCI) size may not change via padding at least scheduled        in CSS. If other DCI format has larger size than DCI format 1_0        such that 1_0 needs to be padded for alignment, it may be        considered as an error case. In this case, other DCI formats may        be truncated to align the size to DCI format 1_0 in CSS. In USS,        the padding may be attached for the maximum size of all DCI        formats sharing the same search space set. Alternatively, the        DCI size may be different depending on the search space set. If        USS is configured in multiple USS, a UE may monitor different        DCI payload sizes in different USS. This may be configured as        ‘monitor both DL scheduling DCI and UL grant’ or ‘monitor        either’. Alternatively, a DCI size monitored in each search        space set may be configured.    -   Option 2: A UE may follow the size configured for each RNTI.        When DCI format related to slot formation indicator (SFI) is to        be monitored in a carrier, the payload size may be configured.        The payload size may always be used for DCI format related to        SFI without additional zero-padding. A payload size of DCI        format related to pre-emption indicator (PI) may be configured        without additional zero-padding. Similarly, DCI format related        to TPC may also have the payload size.    -   Option 3: In one search space set in a slot, particularly, for        CSS, the DCI size may be determined as follows. A payload size        for DCI format related to SFI may be configured.

For DCI format related to PI, the same size as fallback DCI format, i.e.DCI format DCI 1_0, may be used. The size of fallback DCI format may bedetermined based on one of initial DL BWP, current active BWP, orvirtual DL BWP (same as CORESET bandwidth). For DCI format related toTPC, the same size as fallback DCI format, i.e. DCI format DCI 1_0, maybe used.

(2) Case 2: Initial DL/UL BWP after RRC Connection

In this case, the same mechanism used for case 1 mentioned above mayalso be used. If the same configuration of initial DL/UL BWP isconfigured, the behavior needs to be clarified. If a UE is notconfigured with default BWP such that the UE needs to go back to initialBWP upon the timer expires, CORESET used in initial BWP may also bereused.

When RMSI CORESET is reused, DCI size(s) used in RMSI CORESET may beinherited for CSS. The parameters such as REG-CCE mapping, local RSsequence generation, etc., of RMSI CORESET properties may be maintained.But in DCI format 0_0/1_0 in USS, DCI size may be different from thecase the UE monitors DCI before RRC connection, as the configurationsare available. In other words, when a UE reuses RMSI CORESET, DCIformat/size(s) in CSS may be same as initial access, whereas USS mayinherit CORESET properties with potentially different DCI size.

If a UE is configured with SCell or PSCell with assistance on CORESETconfiguration, as RMSI CORESET 0 in a cell may be special, because ithas different REG indexing/RB indexing/sequence mapping compared toother CORESET. Therefore, it also needs to be clarified whether theconfigured CORESET is CORESET 0 of the cell or not. As a default, theconfigured CORESET is not RMSI CORESET of a cell. If it is configured asa RMSI CORESET, a UE may use special mapping in REG mapping/RBmapping/sequence generation/etc.

(3) Case 3: Default DL/UL BWP

(4) Case 4: UE-Specific CSS During BWP Switching

Regarding DCI size, the following options may be considered.

-   -   Option 1: There may be only one DCI size per each configured        search space set. All DCI formats associated with RNTIs        configured with the same search space set may use the same DCI        size via padding. In this option, DCI format 1_0 (i.e.        fallback DCI) size may not change via padding at least scheduled        in CSS. If other DCI format has larger size than DCI format 1_0        such that 1_0 needs to be padded for alignment, it may be        considered as an error case. In this case, other DCI formats may        be truncated to align the size to DCI format 1_0 in CSS. In USS,        the padding may be attached for the maximum size of all DCI        formats sharing the same search space set.

Or, DCI format 1_0 (i.e. fallback DCI) size may be determined based onthe assumption that multiple UEs sharing the same CSS may be configuredwith different BWPs. In this sense, to fix the same size among UEs, DCIfield size may be determined based on non-BWP-specific configurations.If there is BWP-specific configuration, it may be applied to DCIformat(s) in USS or CSS which are not shared with RNTI for broadcastchannel, such as SI-RNTI, P-RNTI, SFI-RNTI, etc. For example, DCI fieldsize may be determined based on initial DL BWP bandwidth and time domainresource allocation information. For another example, the DCI field sizemay be determined based on the bandwidth of CORESET where thecorresponding search space set is configured. In terms of frequencyresource allocation, the same frequency region to CORESET frequency maybe used, or RBs between start and end of PRBs of CORESET may be used forscheduling. Resource allocation frequency region and bandwidth may alsobe configured separately.

In terms of a size of resource allocation field in UL grant, same RAfield size may be used for UL. As UL grant is generally UE-specificonly, as long as resource allocation field size is maintained as thesame, different UL BWP may also be scheduled between different UEs. Interms of determining frequency location of UL BWP scheduled by fallbackUL grant, if the required resource allocation field size is larger thanrequired resource allocation field size of DCI format 1_0, truncation(of most significant bits (MSBs)) may be used. At least in unpairedspectrum, the same frequency region to DL BWP where fallback DCI format1_0 is scheduled may also be used for fallback DCI format 0_0.

Or, in terms of a size of resource allocation field in UL grant, sameresource allocation field size from initial UL BWP may be used.

Or, in terms of a size of resource allocation field in UL grant, maximumresource allocation field size may be used for configured UL BWPs. No ULBWP switching ambiguity is addressed by UE. Even in this case,zero-padding on DCI format 1_0 is not occurred. If the size of DCIformat 0_0 is larger than DCI format 1_0 due to resource allocationfield size, resource allocation field may be truncated until DCI format0_0 has the same size as DCI format 1_0.

Or, in terms of a size of resource allocation field in UL grant,resource allocation field size of fallback DCI 0_0 format may bedetermined as resource allocation field size of DCI format 1_0+{size ofDCI format 1_0−size of DCI format 0_0 (except for resource allocationfield)}. In this case, truncation or zero-pad of resource allocationfield size may be done to meet the size.

Alternatively, DCI field size may be determined based on BWP-specificconfigurations.

Alternatively, the DCI size may be different depending on the searchspace set. If USS is configured in multiple USS, a UE may monitordifferent DCI payload sizes in different USS. This may be configured as‘monitor both DL scheduling DCI and UL grant’ or ‘monitor either’.Alternatively, a DCI size monitored in each search space set may beconfigured.

-   -   Option 2: A UE may follow the size configured for each RNTI.        When DCI format related to slot formation indicator (SFI) is to        be monitored in a carrier, the payload size may be configured.        The payload size may always be used for DCI format related to        SFI without additional zero-padding. A payload size of DCI        format related to pre-emption indicator (PI) may be configured        without additional zero-padding. Similarly, DCI format related        to TPC may also have the payload size.    -   Option 3: In one search space set in a slot, particularly, for        CSS, the DCI size may be determined as follows. A payload size        for DCI format related to SFI may be configured. For DCI format        related to PI, the same size as fallback DCI format, i.e. DCI        format DCI 1_0, may be used. The size of fallback DCI format may        be determined based on one of initial DL BWP, current active        BWP, or virtual DL BWP (same as CORESET bandwidth). For DCI        format related to TPC, the same size as fallback DCI format,        i.e. DCI format DCI 1_0, may be used.

In summary, the followings may be proposed.

(1) No padding is used for DCI format 1_0 if it is scheduled in CSS. Forexample, in initial DL BWP, the size of DCI format 1_0 may be determinedbased on initial DL BWP. To maintain the same DCI size, it may benecessary not to change size of DCI format 1_0 by padding. If the sizeof DCI format 0_0 is larger than DCI format 1_0 due to e.g. largerbandwidth, necessary truncation may be done such that DCI format 1_0 and0_0 can be aligned. This may also be essential for non-initial DL BWP,as the size of DCI format 1_0 can be different among UEs with differentUL BWPs. If DCI format 1_0 size is changed based on a UE's UL BWP, itwill impact on other UEs. In this sense, it seems necessary to fix sizeof DCI format 1_0 when it's scheduled in CSS.

(2) Padding may be done on either DCI format 1_0 or DCI format 0_0 toalign the size if they are scheduled in USS: As there is no impact onother UEs in USS, the DCI size may be determined by the maximum betweenDCI format 1_0 and DCI format 0_0 in USS.

(3) One DCI size per each search space set (except for SFI): There maybe multiple RNTIs configured to a search space set (e.g. SI-RNTI,INT-RNTI, TPC-PUSCH-RNTI), and each related DCI format may havedifferent payload size. As the network can configure separate searchspace set for RNTI(s) with different blind decoding candidates, one DCIsize may be assigned per each CSS for all configured DCI formats. If aCSS includes DCI format 1_0, padding on other DCI formats may be used toalign size to DCI format 1_0. If a CSS does not include DCI format 1_0,the maximum DCI payload size may be used for padding. Also for USS,separate search space set with different DCI size may be configured. AUE may assume that the same DCI size is used for DCI formats sharing thesame search space set.

(4) Frequency resource allocation field size of DCI format 1_0 in CSSmay be determined by the bandwidth of the CORESET. As CSS should be ableto be shared among UEs configured with different BWPs (e.g. narrowbandUEs and wideband UEs), and between BWPs of a single UE (e.g. narrowbandand wideband BWPs), it is not desirable that size of DCI format 1_0varies according to the bandwidth of active DL BWP. Accordingly, DCIformat 1_0 frequency resource allocation in CSS may be determined basedon the CORESET configuration which contains DCI format 1_0 in CSS. Ifthere are multiple CORESETs for that, the lowest CORESET index may beused. There may be only one CSS containing DCI format 1_0 per each BWP.

FIG. 10 shows an example of frequency resource region to allow sharingof CSS among different BWPs according to an embodiment of the presentinvention. FIG. 10-(a) shows a case of CSS sharing within the same UE,i.e. BWP1 and BWP2 of the same UE. FIG. 10-(b) shows a case of CSSsharing across multiple UEs, i.e. BWP1 of UE1 and BWP1 of UE2.

(5) DCI format 0_0 schedules data in the currently active UL BWP: Ifcurrently active UL BWP requires large resource allocation field size,necessary truncation to be aligned with DCI format 1_0 in CSS may beassumed.

(6) In a BWP, to have the same size between DCI format 1_0 withSI-RNTI/RA-RNTI and C-RNTI, it needs to align frequency domain resourceallocation field size. One simple approach is to use the bandwidth ofcurrently active DL BWP. However, this may restrict that broadcastscheduling DCI can be shared among UEs configured with BWPs with thesame BW. Another approach is to configure separate frequency/bandwidthand broadcast scheduling DCI may be scheduled in BWP, which may bedifferent from the currently active DL BWP (can be smaller or equal tothe active DL BWP). In this case, to align DCI sizes among different UEswith different BWP configurations, maximum frequency domain resourceallocation field size for DCI format 1_0 may be configured by higherlayer. That is, the bandwidth and frequency region where DCI format 1_0can schedule with SI-RNTI, RA-RNTI, P-RNTI may be configured in CORESETconfiguration in each DL BWP except for RMSI CORESET. If it is notconfigured, the currently active DL BWP may be used forbandwidth/frequency region. Furthermore, frequency domain resourceallocation field size used in DCI format 1_0 may be configured. If it'snot configured, the field size is determined by the bandwidth ofcurrently active DL BWP.

(7) In addition, size of DCI format 1_0 may also be aligned with DCIformat 0_0. In terms of frequency region/bandwidth for DCI format 0_0,it needs to be clarified that which UL BWP the DCI schedules. Forexample, current active UL BWP may be used. This may lead that size ofDCI format 0_0 changes depending on change of UL BWP. To avoid this,resource allocation field size for DCI format 0_0 may be maximumresource allocation field size among the configured UL BWPs. To alignDCI format 0_0 with DCI format 1_0 shared among multiple UEs withdifferent BWPs, min {configured resource allocation field size for DCIformat 1_0+k, Maximum resource allocation field size among UL BWPs} maybe used. As DCI format 1_0 may have more fields than DCI format 0_0, toalign the size, resource allocation field size for DCI format 0_0 may belarger than that of DCI format 1_1 by the gap k. For example, k may be 6or 7 depending on supplemental UL (SUL) configuration. That is, for DCIformat 0_0, resource allocation field size may be determined inconsideration of configured UL BWPs and DCI format 1_0. Resourceallocation field size of DCI format 0_0 may be defined as min{Configured resource allocation field size for DCI format 1_0+k, maximumresource allocation field size among UL BWPs}, where k bits is the gapbetween DCI format 1_0 and DCI format 0_0 assuming the same resourceallocation field size.

(8) To avoid any RRC configuration, fixed resource allocation field sizemay be used for DCI format 1_0, and the frequency region in an active DLBWP may be defined as the set of PRBs from the lowest PRB in the activeDL BWP.

8. Frequency-Domain Resource Allocation

(1) RBG Size/Number Determination

In determining RBG size, at least two aspects need to be considered.First is how to adjust RBG size depending on bandwidth when active BWPcan be changed dynamically. At least via media access control (MAC)control element (CE) or DCI, BWP can be switched and handling of DCIformat/sizes needs to be addressed. Second aspect is how to handledifferent use cases such as any optimization for DCI schedulingultra-reliable and low latency communications (URLLC) applications, orany optimization for non-slot scheduling in which control overhead cangenerally become relatively larger due to shorter scheduling unitduration.

For the first aspect, semi-statically configured RBG size(s) per BWP forderiving number of RBGs may be preferred, because it can offer theflexible configuration by the network. To support dynamic BWP adaptationwithout changing DCI sizes to minimize reconfiguration ambiguity, thenetwork can configure RBG sizes appropriately. For example, if RBG sizefor BWP1 is X, RBG size for BWP2, which has double bandwidth compared toBWP1, is 2*X. In addition, by semi-statically configured RBG size(s) perBWP, configuration of different RBG sizes per BWP, which will allowbetter multiplexing between UEs utilizing different BWPs, may beconfigured. For example, if a UE with BWP 20 MHz and another two UEswith BWP 10 MHz share the same resource, RBG size for bettermultiplexing (either aligned to 20 MHz or aligned to 10 MHz) may beconfigured. Furthermore, depending on use cases, to minimize DCIoverhead, it may be desirable to have configurability of RBG size.

One consideration of semi-statically configured RBG size(s) per BWP isDCI size when BWP is switched via scheduling DCI. Depending on theselected BWP where potentially different RBG size is configured, it ispossible that different resource allocation field for frequency domainmay be present between old and new BWP. To handle this issue, maximumbit sizes which can cover any resource allocation of the configured BWPsmay be used. This may lead higher overhead. Another approach is toensure the same resource allocation size by proper configuration. Thismay restrict some configuration flexibility.

Alternatively, the overall bit size may be aligned by adjusting the bitfield size for time domain resource allocation depending on the RBGsize, in order to keep the overall bit field size of time-and-frequencyresource allocation as constant regardless of RBG size. In this case,scheduling flexibility on time domain resources will vary depending onthe RBG size. In other words, it can be considered to dependency betweentime-domain resource allocation and frequency-domain resources.

In addition to semi-statically configured RBG size, even within the sameBWP, dynamic switching of RBG size may be allowed. For example, when aUE is configured with relatively large BWP and RBG size is generallylarge, if the UE does not have so much data to be scheduled with, it maybe desirable to have smaller RBG size to enjoy frequency diversity andbetter multiplexing with other UEs. To address this issue, eithersmaller BWP may be activated which can lead switching time overhead, orsmaller RBG size may be used for better resource allocation flexibility.To support such dynamic switching of RBG sizes (e.g. between two RBGsizes) while keeping the same DCI overhead, the same number of RBGsindicated by DCI frequency resource allocation may be maintained. Inother words, the overall resource allocation field size may be fixed anda combination of schedulable RBGs (the number of RBGs) and RBG sizes maybe maintained such that the required bitmap size would not change withBWP switching.

FIG. 11 shows an example for frequency-domain resource allocation for agiven BWP according to an embodiment of the present invention. FIG.11-(a) shows a case of large RB size. FIG. 11-(b) shows a case of smallRBG size.

Resource allocation consisting of RBG size and RBG bitmap within abandwidth may be indicated by DCI. RBG bitmap may indicate all RBGswithin a given BWP, and its bit field size may vary depending on theindicated RBG size. Alternatively, to keep the bit field size constant,RBG index set to be indicated by DCI may be restricted, as shown in FIG.11-(b).

RBG size may also be different depending on use case or the latency andreliability requirements. For example, compact DCI for URLLC use casesmay be realized by increasing RBG size. For another example, betweenslot and multi-slot, different RBG size may be used unless it is for thealignment of DCI sizes. To support various use cases, RBG size may beconfigured per DCI format for each BWP configuration.

(2) PRB Grid and PRB Indexing

A UE may be indicated with the offset between the lowest frequency andthe center of SS block so that the UE has accessed for common PRBindexing. Based on the information, unless other information is alsogiven, it is natural to construct PRB grid based on the SS block. Giventhe offset between the center of SS block and the lowest frequency, thenumber of subcarriers/RBs may be placed where the lowest frequency needsto be indicated per different numerology or subcarrier spacing.

In terms of indicating the offset between the lowest frequency and thecenter of SS block, (1) number of RBs of a given numerology may beindicated or (2) number of subcarriers of a given numerology may beindicated. If PRB grid of PBCH and RMSI transmission is the same as PRBgrid of other transmissions, it is natural to use number of RBs as theoffset. This, however, may restrict synchronization raster which needsto be at least RB bandwidth of the larger subcarrier spacing usedbetween PBCH and RMSI. Alternatively, subcarrier grid of PBCH/RMSItransmission may be maintained because the same as subcarrier grid ofother transmissions where the offset can be given as multiple ofsubcarriers.

To minimize ambiguity, PRB grid of PBCH and RMSI may be same as that ofother transmission. Furthermore, to have aligned PRB grids amongdifferent UEs accessing different SS block, the gap between SS blocksmay be at least multiple RBs based on the numerology used for PBCH.Moreover, to have aligned PRB between wideband and narrowband UEs, thegap between SS block and carrier center may also be multiple of RBsbased on the numerology used for PBCH. For better PRB grid structure(e.g. more symmetric structure), subcarrier 0 of each numerology may bealigned at the center of a carrier. However, for different numerology,the gap may not be multiple of RBs depending on the gap. Thus, the gapbetween SS block and center of the carrier may be multiple of RBs of thelargest subcarrier spacing that frequency band supports. In other words,subcarrier 0 of each numerology may be aligned with center of SS block.Or, PRB offset between subcarrier 0 and SS block may be indicated interms of number of RBs based on the numerology used for PBCH.

FIG. 12 shows an example of indicating PRB offset between subcarrier 0and SS block in terms of number of RBs based on the numerology used forPBCH according to an embodiment of the present invention. Referring toFIG. 12, to align different numerology PRB grid around center, it may benecessary to indicate appropriate offset. In other words, offset betweenSS block and the lowest frequency may be indicated as the number of RBsof a given numerology, and additional PRB grid offset for a numerologymay be necessary which can be indicated as multiple of RBs based on thenumerology used in PBCH. This may be realized by indicating offset interms of number of RBs based on the numerology used in PBCH.

9. Details of Time Domain Resource Allocation

(1) One Slot Case

Considering dynamic TDD system, explicit indication of time-domainresource allocation may be used to schedule DL channels and UL channelsin a slot in a dynamic manner. In this case, for efficient design oftime-domain resource allocation scheme, it may be helpful to know whichslot formats (which indicate DL portion, gap, and/or UL portion within aslot) will be supported in NR. Meanwhile, at least, scheduled DLresources may be different compared to slot format to be indicated bygroup-common PDCCH. For instance, in case of scheduled DL resources forPDSCH transmission, data transmission may start after CORESET to avoidoverlapping between DL CORESET and PDSCH. Furthermore, when differentguard period (GP) is used UE-specifically, end position of DwPTS may bedifferent per each UE which can be dynamically indicated in DCI.Furthermore, different data rate matching for CSI-RS, UCI, SRS, etc.,may be expected per UE depending on its numerology/measurementconfigurations. In this sense, indicating the same start and endposition for a group of UEs may not be efficient. Even though slotformat is dynamically indicated or fixed, UE-specific dynamic indicationof starting and duration of PDSCH and PUSCH may be necessary. However,semi-static starting and duration may also be considered, particularlyfor broadcast channels such as RMSI, OSI, initial-access messages, etc.

To minimize DCI overhead and scheduling flexibility, two options mayconsidered. First option is to utilize resource indication value(RIV)-like approach, where the possible start OFDM symbols for PDSCH orPUSCH is rather restricted (e.g. for PDSCH: 0, 1, 2, 3, for PUSCH:K+offset+0, K+offset+1, K+offset+2, K+offset+2, where K is the last OFDMsymbol index of CORESET and offset is the offset between control regionand the start of PUSCH for processing time, TA, switching gap, etc. theoffset may be configured per each UE). Additionally, to supportcross-slot scheduling, slot index may be needed. Second option is toconfigure a set of time domain resource patterns by RRC signaling. Forinstance, multiple sets of slot index, start OFDM symbol index and endOFDM symbol index within a slot may be configured by RRC signaling, andL1 signaling may indicate one of the set for time domain resourceallocation.

For instance, when PDSCH or PUSCH is scheduled by DCI associated withsearch space for RMSI, time domain resource allocation for PDSCH orPUSCH may be configured by PBCH, RMSI, or OSI. Alternatively,considering signaling overhead, slot index and/or start OFDM symbolindex may be fixed. For example, slot index of PDSCH may be the same asslot index of its associated PDCCH, while slot index of PUSCH may befixed value (e.g. 4 slots) after its associated PDCCH transmission.Next, start OFDM symbol index of PDSCH may be set to OFDM symbol indexright after CORESET duration.

(2) Multi Slot Case

Main motivation of multi-slot aggregation is to enhance detectionperformance of a TB by using repetition in time domain. It may bebeneficial in terms of decoding complexity that PDSCH or PUSCHtransmission is self-decodable in each aggregated slot. In other words,a single PDSCH or PUSCH may be mapped within a slot rather than acrossmultiple aggregated slots.

In terms of resource allocation, multi-slot aggregation may need tosupport non-contiguous time domain resource allocation. For instance, ULtransmission with multi-slot aggregation may need to reserve DLresources for possible DL control channel at the beginning of eachaggregated slot. Similarly, DL transmission with multi-slot aggregationmay need to reserve UL resources for UL control channel at the end ofaggregated slot(s). These kinds of slot formats in terms of DL portionand UL portion may be different slot-by-slot. The following options maybe considered for time domain resource allocation across multipleaggregated slots.

-   -   Option 1: Scheduling DCI may indicate one of RRC configured sets        for time domain resource allocation parameters across aggregated        slots.    -   Option 2: Time domain resource allocation parameters for one        slot case may be applied to all the aggregated slots.    -   Option 3: Time domain resource allocation parameters for one        slot case may be applied to certain aggregated slot(s).        Remaining time domain resources across aggregated slot may be        configured by additional RRC signalling and/or DCI indication.

For Option 1, RRC configured set for time-domain resource allocation mayconsist of start slot index, end slot index (or the number of aggregatedslots), start OFDM symbol index within a slot for each aggregated slot,and end OFDM symbol index within a slot for each aggregated slot. Inother words, it is necessary to configure RRC configured sets formulti-slot case in addition to RRC configured set for one slot case.Since the number of parameters within a set would be large, it may beinefficient in terms of scheduling flexibility if the resourceallocation bit field size is kept to be constant. Alternatively, it mayneed to increase resource allocation bit field size for multi-slot casecompared to one slot case.

For Option 2, since time domain resource allocation for one slot case isapplied to all the aggregated slots consistently, it may not need tohave additional RRC configuration or DCI bit field to support multi-slotcase. However, it may be inefficient in terms of resource usage. Forinstance, to guarantee potential UL (or DL) transmission(s) during theaggregated slots, scheduled DL (or UL) resources in time domain may beunnecessarily smaller than the overall DL (or UL) resources in timedomain across aggregated slots, respectively.

RRC configuration and DCI indication for time domain resource allocationfor one slot case may need to be reused for multi-slot case consideringRRC and DCI overhead. Furthermore, to enhance scheduling flexibility,addition overhead on RRC signaling and/or DCI indication may be needed.Accordingly, Option 3 may be taken into account considering trade-offbetween signaling overhead and scheduling flexibility.

Alternatively, slot format related information transmitted ingroup-common PDCCH may be used to update time domain resources of PDSCHor PUSCH in aggregated slots. However, UE may need to successfullydetect both DCI scheduling PDSCH or PUSCH and group-common PDCCH.Furthermore, for data mapping purpose, at the scheduling, SFI for thescheduled slots needs to be known. If slot format is changed afterscheduling data, it may cause ambiguity regarding the overall availableREs. If group common PDCCH changes slot format dynamically, time domainresources for data rate matching may be configured/indicated, andpuncturing may be performed if slot format is changed in the middle ofmulti-slot scheduling.

Another issue is whether a common time domain resource allocation isused to indicate ‘same-slot’, ‘cross-slot’ and ‘multi-slot aggregation’scheduling. When dynamic BWP adaptation is achieved and cross-slotscheduling is necessary to accommodate radio frequency (RF) retuninglatency, it may be desirable that same-slot and cross-slot schedulingcan be indicated dynamically. In terms of multi-slot aggregation, it maybe configured by the network. If multi-slot aggregation is configured,DCI may carry multi-slot aggregation which can include ‘single-slot’ and‘cross-slot’ within the maximum number of schedulable multi-slots.

(3) Non Slot Case

There may be some differences between slot-based scheduling andmini-slot based scheduling at least in terms of DM-RS position. Further,different DCI format may be used for each scheduling. It may benecessary to clarify how slot-based scheduling and mini-slot basedscheduling are differentiated. Overall, two approaches may beconsidered.

-   -   Implicitly: Mini-slot based scheduling and slot based scheduling        may be distinguished based on the monitoring occasion of PDCCH        and its periodicity. For instance, if scheduling DCI is        associated with CORESET and its periodicity is multiples of        slots, scheduling may be slot based scheduling. Otherwise, the        scheduling may be mini-slot based scheduling.    -   Explicitly: Each CORESET may be configured with either slot        based scheduling or mini-slot based scheduling, and DCI        scheduled in that CORESET may schedule either slot-based data or        mini-slot based data.

As mini-slot based scheduling may also be configured with one slotmonitoring interval and monitoring may occur only in middle of slot by 7OFDM symbol mini-slot size, slot-based scheduling may be assumed whenCORESET monitoring periodicity is multiple of slots, unless it isindicated as mini-slot based scheduling. For mini-slot based scheduling,explicit indication of mini-slot based scheduling may be configured ineach CORESET for mini-slot scheduling.

Non-slot case is mainly used for URLLC application. In this case,considering latency, PDCCH needs to be transmitted no later than itsassociated PDSCH or PUSCH transmission. Specifically, it is impossibleto transmit PUSCH before decoding UL grant (except for UL transmissionwithout grant). In case of PDSCH, UE may need to have unnecessarilyexcessive buffer before decoding DCI scheduling the PDSCH. For lowlatency, the timing difference between PDCCH and PDSCH/PUSCH needs to besmall enough. Accordingly, start OFDM symbol index and end OFDM symbolindex for non-slot case does not need to be defined with respect to slotboundary.

10. Details of TBS Determination

(1) Parameters of Formula for TBS Determination

When TBS determination is performed based on formula, it is necessary tomake clear definition of parameters to be used for TBS determination.First, there may be no ambiguity on the meaning of the number of layersthe codeword is mapped onto and modulation order. Next, the definitionof coding rate is given by following options.

-   -   Option 1: Coding rate is the ratio of TBS to the number of        overall coded bits.    -   Option 2: Coding rate is the ratio of TBS plus cyclic redundancy        check (CRC) size(s) to the number of overall coded bits.

Coding rate is defined by the ratio of the number of information bits tothe number of coded bit, and the number of coded bits may be a sum ofthe number of information bits and the number of parity (redundancy)bits. Since CRC is a kind of error detection code and it is derived fromTBS, CRC may be seen as redundancy bits. On the other hand, from theperspective of low-density parity check (LDPC) coding, its input streamis given by TBS and CRC (CB CRC and parts of TB CRC). Therefore, CRC canbe considered to be included in information bits.

Option 1 may be preferred for the definition of coding rate to ensurethe same set of TBS between different base graph and its associated CRClength (e.g. 24 bits for BG 1, and 16 bits for BG 2) are used.

Regarding time/frequency resource to which the PDSCH/PUSCH is scheduled,the reference number of REs to be considered for TBS determination needsto be defined, considering some aspects such as whether or not DM-RS isincluded in the time/frequency resources to which the PDSCH/PUSCH isscheduled. The following options may be considered.

-   -   Option 1: The number of REs scheduled by resource allocation        regardless of actual mapping of PDSCH or PUSCH.    -   Option 2: The number of REs to be used only for PDSCH or PUSCH        without DM-RS.    -   Option 3: The number of REs to be used only for PDSCH or PUSCH        including DM-RS.

For Option 1, the number of REs may be given by multiplication of thenumber of allocated symbols and the number of allocated subcarriers. Forthe same number of REs scheduled by DCI, the actual number of REs to beused for PDSCH or PUSCH mapping may depend on the rate-matching pattern(due to the dynamic resource sharing between PDCCH and PDSCH or othersignals). In this case, TBS control may be much simpler since it justneeds to consider only resource allocation field in DCI. However, it maycause large difference between the indicated coding rate and theeffective coding rate after rate-matching.

Option 2 may guarantee the effective coding rate after rate-matching isequal to the indicated coding rate. However, since small changes on thenumber available REs can cause different value of TBS, it may bedifficult to perform TBS control. Specifically, the network may restrictscheduled resources to achieve target TBS value, which is based on MACmessages to be transmitted. Otherwise, zero padding may be performed inMAC layer. Regarding DM-RS, it may need to be guaranteed that the samevalue of TBS is supported regardless of the DM-RS density.

Accordingly, as in Option 3, the number of available REs used for PDSCHor PUSCH may include DM-RS.

For TBS determination, it may be necessary to consider decoupling ofmodulation order and coding rate. In LTE, the same value of TBS issupported for the switching point of modulation order for schedulingflexibility. For simplicity, DCI may indicate modulation order andcoding rate separately. However, to support the same TBS for differentmodulation order, coding rates to be indicated by DCI may be restricted.For instance, to support the same TBS for 16QAM and 64QAM, it may benecessary that DCI can indicate coding rate of R, coding rate of 4/6*R,and coding rate of 6/4*R. Depending on the DCI overhead, design ofindication of coding rate may be restricted.

Alternatively, it may be considered to introduce scaling factor to beused in formula for TBS determination. In this case, coding rate andmodulation order may be jointly indicated by MCS field in DCI, andscaling factor may be used to increase or decrease TBS value bymultiplying scaling factor to the formula for TBS determination, withoutchanges on other parameters such as scheduled resources, coding rate,and modulation order. For instance, the set of scaling factor values maybe given by {1, 1/2, 4/6, 6/8} to schedule the same TBS betweendifferent modulation orders. In this case, scaling factor may beindicated by RRC signaling and/or DCI. Meanwhile, scaling factor may beused to ensure to enable the same TBS between initial transmission andre-transmission with the same/different number of PRBs or thesame/different number of symbols.

(2) Special TBS Handling

Considering certain services or applications (e.g. VoIP), it may beneeded to support specific value(s) of TBS. When the TBS determinationis based on look-up table, then the specific value(s) of TBS may bemapped on the table. If the formula-based TBS determination is employed,special setting of DCI field(s) may be defined to indicate specificvalue of TBS. For instance, scaling factor may have reserved state, andif the reserved state is indicated by DCI, TBS determination may beperformed based on look-up table containing specific value(s) of TBSinstead of TBS formula. Alternatively, TBS may be derived from look-uptable if its reference number of CB is equal to 1. Otherwise,formula-based TBS determination may be used.

(3) TBS Determination for Multi-Slot Aggregation

Even though multi-slot aggregation is configured and used, the maximumTBS may be determined based on the one slot case. Assuming thatmulti-slot aggregation is used for scheduling each TB in each slotrepeatedly, TBS determination for multi-slot aggregation case may bedependent on MCS and reference REs in a slot. In terms of defining thereference REs in a slot, the smallest or average or the largest REsamong the scheduled slots may be considered. For example, if there arefull slot scheduled and the largest reference REs is chosen, full slotcase may be used for TBS determination. If multi-slot is also supportedfor mapping a TB across multiple slot without repetition/retransmission,TBS computation of single slot case may be expanded to the multiple slotcase.

In the first case, TBS may have upper limit even though the number ofREs to be used for PDSCH or PUSCH increases further compared to one slotcase. In this case, it may be necessary to clarify the definition oftime/frequency resource to which the PDSCH/PUSCH is scheduled formulti-slot case. TBS determination for multi-slot case has followingoptions:

-   -   Option 1: Reference number of REs for a certain aggregated slot        may be used for TBS determination.    -   Option 2: Average value of reference number of REs over all the        aggregated slots may be used for TBS determination.

Regarding Option 1, the certain aggregated slot to be used for TBSdetermination may be the first aggregated slot, or aggregated slot whosereference number of REs is the largest or smallest. In this case, TBScontrol may be quite simple by adjusting reference number of REs for acertain aggregated slot. In case of Option 2, TBS may be determined byconsidering all the aggregated slots.

FIG. 13 shows a method for monitoring DCI by a UE according to anembodiment of the present invention. The present invention describedabove for UE side may be applied to this embodiment.

In step S1300, the UE monitors first DCI having a first size in USS. Thefirst size is determined based on an active BWP. In step S1310, the UEmonitors second DCI having a second size in CSS. The second size isdetermined based on a default BWP.

The second DCI may be a fallback DCI. The default BWP may be an initialBWP.

The first DCI may schedule UE-specific data. The second DCI may schedulecell-specific broadcast data or UE-specific data.

The first DCI or the second DCI may be monitored in at least one slot.The first DCI or the second DCI may include first information on anindex of a start slot of the at least one slot and second information ona combination of a start symbol and a length of symbols in each of theat least one slot.

According to embodiment of the present invention shown in FIG. 13, amongUEs having different active BWPs, DCI format for scheduling broadcastchannel and fallback DCI format, i.e. DCI format 0_0 or DCI format 1_0,can always have same size. Therefore, reliability of monitoring DCIformat for scheduling broadcast channel and fallback DCI format can beenhanced.

FIG. 14 shows a UE to implement an embodiment of the present invention.The present invention described above for UE side may be applied to thisembodiment.

A UE 1400 includes a processor 1410, a memory 1420 and a transceiver1430. The processor 1410 may be configured to implement proposedfunctions, procedures and/or methods described in this description.Layers of the radio interface protocol may be implemented in theprocessor 1410. Specifically, the processor 1410 controls thetransceiver 1430 to monitor first DCI having a first size in USS. Thefirst size is determined based on an active BWP. Furthermore, theprocessor 1410 controls the transceiver 1430 to monitor second DCIhaving a second size in CSS. The second size is determined based on adefault BWP. The second DCI may be a fallback DCI. The default BWP maybe an initial BWP. The first DCI may schedule UE-specific data. Thesecond DCI may schedule cell-specific broadcast data or UE-specificdata. The first DCI or the second DCI may be monitored in at least oneslot. The first DCI or the second DCI may include first information onan index of a start slot of the at least one slot and second informationon a combination of a start symbol and a length of symbols in each ofthe at least one slot.

The memory 1420 is operatively coupled with the processor 1410 andstores a variety of information to operate the processor 1410. Thetransceiver 1420 is operatively coupled with the processor 1410, andtransmits and/or receives a radio signal.

According to embodiment of the present invention shown in FIG. 14, theprocessor 1410 can control the transceiver 1430 to monitor DCI formatfor scheduling broadcast channel and fallback DCI format reliably.

FIG. 15 shows a method for transmitting DCI by a BS according to anembodiment of the present invention. The present invention describedabove for BS side may be applied to this embodiment.

In step S1500, the BS transmits first DCI having a first size in USS.The first size is determined based on an active BWP. In step S1510, theBS transmits second DCI having a second size in CSS. The second size isdetermined based on a default BWP.

The second DCI may be a fallback DCI. The default BWP may be an initialBWP.

The first DCI may schedule UE-specific data. The second DCI may schedulecell-specific broadcast data or UE-specific data.

The first DCI or the second DCI may be monitored in at least one slot.The first DCI or the second DCI may include first information on anindex of a start slot of the at least one slot and second information ona combination of a start symbol and a length of symbols in each of theat least one slot.

According to embodiment of the present invention shown in FIG. 15, theBS can transmit DCI format for scheduling broadcast channel and fallbackDCI format, i.e. DCI format 0_0 or DCI format 1_0, which have same size,to UEs configured with different active BWPs. Therefore, reliability ofmonitoring DCI format for scheduling broadcast channel and fallback DCIformat can be enhanced.

FIG. 16 shows a BS to implement an embodiment of the present invention.The present invention described above for BS side may be applied to thisembodiment.

A UE 1600 includes a processor 1610, a memory 1620 and a transceiver1630. The processor 1610 may be configured to implement proposedfunctions, procedures and/or methods described in this description.Layers of the radio interface protocol may be implemented in theprocessor 1610. Specifically, the processor 1610 controls thetransceiver 1630 to transmit first DCI having a first size in USS. Thefirst size is determined based on an active BWP. Furthermore, theprocessor 1610 controls the transceiver 1630 to transmit second DCIhaving a second size in CSS. The second size is determined based on adefault BWP. The second DCI may be a fallback DCI. The default BWP maybe an initial BWP. The first DCI may schedule UE-specific data. Thesecond DCI may schedule cell-specific broadcast data or UE-specificdata. The first DCI or the second DCI may be monitored in at least oneslot. The first DCI or the second DCI may include first information onan index of a start slot of the at least one slot and second informationon a combination of a start symbol and a length of symbols in each ofthe at least one slot.

The memory 1620 is operatively coupled with the processor 1610 andstores a variety of information to operate the processor 1610. Thetransceiver 1620 is operatively coupled with the processor 1610, andtransmits and/or receives a radio signal.

According to embodiment of the present invention shown in FIG. 16, theprocessor 1610 can control the transceiver 1630 to transmit DCI formatfor scheduling broadcast channel and fallback DCI format reliably.

The processors 1410, 1610 may include application-specific integratedcircuit (ASIC), other chipset, logic circuit and/or data processingdevice. The memories 1420, 1620 may include read-only memory (ROM),random access memory (RAM), flash memory, memory card, storage mediumand/or other storage device. The transceivers 1430, 1630 may includebaseband circuitry to process radio frequency signals. When theembodiments are implemented in software, the techniques described hereincan be implemented with modules (e.g., procedures, functions, and so on)that perform the functions described herein. The modules can be storedin memories 1420, 1620 and executed by processors 1410, 1610. Thememories 1420, 1620 can be implemented within the processors 1410, 1610or external to the processors 1410, 1610 in which case those can becommunicatively coupled to the processors 1410, 1610 via various meansas is known in the art.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

What is claimed is:
 1. A method performed by a wireless device operatingin a wireless communication system, the method comprising: monitoring,by the wireless device, downlink control information (DCI) in either aUE specific search space (USS) or a common search space (CSS), whereinthe DCI includes information related to a frequency resource to which adownlink data is scheduled; and receiving, by the wireless device from anetwork via the frequency resource, the downlink data scheduled by theDCI, wherein based on that the DCI is monitored in the USS: (i) thedownlink data includes data specified to the wireless device, and (ii) asize of the information related to the frequency resource is determinedbased on an activated bandwidth part (BWP) among BWPs assigned to thewireless device, and wherein based on that the DCI is monitored in theCSS: the downlink data includes at least one of remaining minimum systeminformation (RMSI), a random access response (RAR), or a paging.
 2. Themethod of claim 1, wherein a size of the information related to thefrequency resource is determined based on an initial BWP among BWPsassigned to the wireless device.
 3. The method of claim 1, wherein theDCI is monitored in at least one slot.
 4. The method of claim 3, whereinthe DCI includes information related to an index of a start slot of theat least one slot and information related to a combination of a startsymbol and a length of symbols in each of the at least one slot.
 5. Awireless device configured to operate in a wireless communicationsystem, the wireless device comprising: a transceiver, a processor; anda memory operably coupled to the processor and storing instructionsthat, based on being executed by the processor, control the wirelessdevice to perform operations comprising: monitoring downlink controlinformation (DCI) in either a UE specific search space (USS) or a commonsearch space (CSS), wherein the DCI includes information related to afrequency resource to which a downlink data is scheduled; and receiving,from a network via the frequency resource, the downlink data scheduledby the DCI, wherein based on that the DCI is monitored in the USS: (i)the downlink data includes data specified to the wireless device, and(ii) a size of the information related to the frequency resource isdetermined based on an activated bandwidth part (BWP) among BWPsassigned to the wireless device, and wherein based on that the DCI ismonitored in the CSS: the downlink data includes at least one ofremaining minimum system information (RMSI), a random access response(RAR), or a paging.
 6. The wireless device of claim 5, wherein a size ofthe information related to the frequency resource is determined based onan initial BWP among BWPs assigned to the wireless device.
 7. Thewireless device of claim 5, wherein the DCI is monitored in at least oneslot.
 8. The wireless device of claim 7, wherein the DCI includesinformation related to an index of a start slot of the at least one slotand information related to a combination of a start symbol and a lengthof symbols in each of the at least one slot.
 9. A processing apparatusconfigured to control a wireless device to operate in a wirelesscommunication system, the processing apparatus comprising: a processor;and a memory operably coupled to the processor and storing instructionsthat, based on being executed by the processor, control the wirelessdevice to perform operations comprising: monitoring downlink controlinformation (DCI) in either a UE specific search space (USS) or a commonsearch space (CSS), wherein the DCI includes information related to afrequency resource to which a downlink data is scheduled; and receiving,from a network via the frequency resource, the downlink data scheduledby the DCI, wherein based on that the DCI is monitored in the USS: (i)the downlink data includes data specified to the wireless device, and(ii) a size of the information related to the frequency resource isdetermined based on an activated bandwidth part (BWP) among BWPsassigned to the wireless device, and wherein based on that the DCI ismonitored in the CSS: wherein the downlink data includes at least one ofremaining minimum system information (RMSI), a random access response(RAR) or a paging.
 10. The processing apparatus of claim 9, wherein asize of the information related to the frequency resource is determinedbased on an initial BWP among BWPs assigned to the wireless device. 11.The processing apparatus of claim 9, wherein the DCI is monitored in atleast one slot.
 12. The processing apparatus of claim 11, wherein theDCI includes information related to an index of a start slot of the atleast one slot and information related to a combination of a startsymbol and a length of symbols in each of the at least one slot.